Skocz do pozycji: 1.

Tytuł:

Simplified models of macrosegregation
Uproszczone modele makrosegregacji

Autorzy:

Mochnacki, B.
Suchy, J. S.

Powiązania:

https://bibliotekanauki.pl/articles/280309.pdf

Data publikacji:

2006

Wydawca:

Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej

Tematy:

macrosegregation
solidification
numerical simulation

Opis:

The macrosegregation process takes place during typical solidification of alloys. Fractions of alloy components in a liquid and solid sub-domains are time-dependent and determined by the course of border lines on the equilibrium diagram. From the mathematical point of view, the process is described by a system of partial differential equations (diffusion equations) and boundary-initial conditions. The process is coupled with the solidification one. In this paper, simplified models of macrosegregation are discussed. The volumetric solidification and the 'sharp' solid-liquid interface are considered. Examples of computations are also shown. It seems that for practical applications, the methods proposed are sufficiently exact. Additionally, they are very simple for numerical realization.
W pracy przedstawiono opis matematyczny procesu segregacji składników stopowych w objętości krzepnącego odlewu. Wskazano na trudności związane z rozwiązaniem odpowiedniego problemu brzegowo-początkowego, a w dalszej części artykułu przedstawiono propozycje rozwiązań przybliżonych. Rozpatrywano zarówno problem krzepnięcia objętościowego, jak i klasyczne zadanie Stefana. Rozważania teoretyczne zilustrowano przykładami obliczeń numerycznych.

Źródło:

Journal of Theoretical and Applied Mechanics; 2006, 44, 2; 367-379
1429-2955

Pojawia się w:

Journal of Theoretical and Applied Mechanics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 2.

Tytuł:

A digital cartographic source for numerical models in hydrology

Autorzy:

Szpakowski, W.
Szulwic, J.

Powiązania:

https://bibliotekanauki.pl/articles/1933151.pdf

Data publikacji:

2007

Wydawca:

Politechnika Gdańska

Tematy:

digital cartography
GIS
numerical simulation

Opis:

A short review of digital data used in hydrological models is presented. There are three basic kinds of digital maps used in hydrology: raster images (scan, orthophotomap), vector maps and digital models (Digital Terrain, Landscape and Elevation Models). Hydrological models are used to analyze natural phenomena: free surface flow, the precipitation-outflow relation and groundwater flow. The choice of cartographic source depends on the problem to be solved. The article includes an analysis of two problems: (i) the solution of flood area due to extreme river flow and (ii) groundwater flow. In both cases, digital cartographic sources are presented.

Źródło:

TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2007, 11, 4; 449-461
1428-6394

Pojawia się w:

TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 3.

Tytuł:

Load positioning and minimization of load oscillations in rotary cranes
Pozycjonowanie i minimalizacja wahań ładunku w żurawiach obrotowych

Autorzy:

Maczyński, A.

Powiązania:

https://bibliotekanauki.pl/articles/280720.pdf

Data publikacji:

2003

Wydawca:

Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej

Tematy:

crane
positioning
control
numerical simulation

Opis:

In the paper a method of load positioning and minimization of load final oscillations in rotary cranes has been presented. Drive functions of the slewing of an upper structure have been determinated by means of dynamic optimisation. In the optimisation task a simplified model has been used. A completely stiff supporting structure of the crane has been assumed. A feedback control system has been proposed to compensate for influences of flexibilities that have not been taken into account during the optimisation and for inaccurate knowledge of parameters of the model. The effectiveness of the control system for two different controlled variables has been analysed. A special coefficient for quantitative analysis has been proposed. Results of numerical simulations have been presented.
W pracy zaprezentowano metodę pozycjonowania i minimalizacji końcowych wahań ładunku w żurawiach obrotowych. Funkcja napędowa obrotu nadwozia została dobrana na drodze optymalizacji dynamicznej dla uproszczonego modelu zakładającego całkowitą sztywność układu nośnego żurawia. Zaproponowano układ regulacji kompensujący wpływ nieuwzględnionych podczas optymalizacji podatności i niedokładnej znajomości parametrów modelu. Do ilościowej oceny jakości pozycjonowania zaproponowano specjalny wskaźnik. Zaprezentowano wyniki symulacji numerycznych.

Źródło:

Journal of Theoretical and Applied Mechanics; 2003, 41, 4; 873-885
1429-2955

Pojawia się w:

Journal of Theoretical and Applied Mechanics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 4.

Tytuł:

Characterization of different one-stage blower designs using three-dimensional unsteady numerical flow simulation

Autorzy:

Kalmar, L.
Janiga, G.
Fodor, B.
Soltesz, L.

Powiązania:

https://bibliotekanauki.pl/articles/175582.pdf

Data publikacji:

2014

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

blower
numerical simulation
unsteady flow

Opis:

This paper deals with the computational fluid dynamics investigation of the flow in a one-stage radial flow blower-aggregate. The main aim of this numerical study is to compute the relevant operating characteristics of the blower and to determine detailed information about the flow characteristics inside it. The distributions of these flow characteristics in the blower determined by the commercial code are available to judge whether the elements of the blower are working properly, or not. The calculated characteristics of operating parameters are compared with measured data given by experimental tests of the blower-aggregate for their validation.

Źródło:

Transactions of the Institute of Fluid-Flow Machinery; 2014, 126; 55-64
0079-3205

Pojawia się w:

Transactions of the Institute of Fluid-Flow Machinery

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 5.

Tytuł:

Computation and experimental comparison of the deformation behavior of pantographic structures with different micro-geometry under shear and torsion

Autorzy:

Yang, Hua
Müller, Wolfgang H.

Powiązania:

https://bibliotekanauki.pl/articles/281645.pdf

Data publikacji:

2019

Wydawca:

Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej

Tematy:

nonlinear elasticity
metamaterial
numerical simulation

Opis:

Additive manufacturing methods, commonly known as 3D printing, allow more sophisticated designs to be created. Willingly designed substructures incorporated into the solid open up new possibilities for uncommon macroscopic deformation behavior. Such a man-made structure is also referred to as a metamaterial. A detailed simulation of a polymer-based metamaterial is challenging but accurately possible by means of the theory of elasticity. In this study, we present experimental investigations of a metamaterial composed of pantographic substructures of different internal geometry. The pantographic structures show an unexpected type of deformation, which can be modeled via elasticity with the aid of direct numerical simulation by using the Finite Element (FE) method. In other words, a detailed mesh is generated involving the substructure. The metamaterial is additively manufactured out of a common polymer showing nonlinear elastic deformation and, therefore, hyperelastic material models are used. Specifically, analytical solutions of a circular cylinder are examined and compared in the case of extension and torsion in order to comprehend the effects of the coefficients inherent to the energy function of the hyperelastic model. Finally, FE computations of pantographic structures are performed and compared with the experimental measurements.

Źródło:

Journal of Theoretical and Applied Mechanics; 2019, 57, 2; 421-434
1429-2955

Pojawia się w:

Journal of Theoretical and Applied Mechanics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 6.

Tytuł:

Development and verification of the scale formation model during high temperature oxidation for S235 steel

Autorzy:

Przyłucka, Aleksandra
Cebo-Rudnicka, Agnieszka
Rywotycki, Marcin
Augustyn-Nadzieja, Joanna
Malinowski, Zbigniew

Powiązania:

https://bibliotekanauki.pl/articles/29520237.pdf

Data publikacji:

2020

Wydawca:

Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH

Tematy:

scale
numerical simulation
model of oxidation

Opis:

Every year rapid industrialization and the following urbanization fuel the global demand for steel. The use of steel products contributes to the sustainable development of society. The scale growth mechanism accompanies the high-temperature plastic working of metals and alloys. The article focuses on the thickness of the scale formed as a result of annealing steel samples in a furnace. Samples made of S235 (A283C) steel were heated at two temperatures, 1100ºC and 1200ºC, for 8 minutes. The amount of scale formed was determined on the basis of photos taken with a light microscope. The transformed equations of steel oxidation kinetics were used in the computational part. The scale thickness obtained numerically corresponded to the scale formed in real conditions. The aim of the research was to adjust the scale growth model on steel so that it gives correct results in relation to the actual thickness of the formed oxidized layer.

Źródło:

Computer Methods in Materials Science; 2020, 20, 4; 139-146
2720-4081
2720-3948

Pojawia się w:

Computer Methods in Materials Science

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 7.

Tytuł:

Optimization of well placement and control to maximize CO2 trapping during geologic sequestration

Autorzy:

Stopa, J.
Janiga, D.
Wojnarowski, P.
Czarnota, R.

Powiązania:

https://bibliotekanauki.pl/articles/298725.pdf

Data publikacji:

2016

Wydawca:

Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH

Tematy:

CO2 sequestration
optimization
numerical simulation

Opis:

The CO2 injection into geological formations such as saline aquifers can be effective method of sequestration enabling efficient immobilization of gas by surface and capillary forces. The main objective of presented method of optimization was to determine optimal well position and injection rates that maximize residual trapping. This would mitigate the risk of the CO2 leakage outside of storage zone. A genetic algorithm and particle swarm optimization have been developed and coupled with reservoir simulator to optimally examine various placement and injection control strategies for vertical as well as horizontal well. Optimization was carried out in 3D heterogeneous real field model with water-CO2 -formation rock relationship. Numerical examples confirm that developed algorithm can find a promising optimal solution effectively within a partial number of simulation runs.

Źródło:

AGH Drilling, Oil, Gas; 2016, 33, 1; 93-104
2299-4157
2300-7052

Pojawia się w:

AGH Drilling, Oil, Gas

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 8.

Tytuł:

Derivation of Closed-Form Design Equations for Idealized Operation of Inverse Class-E Power Amplifiers at Any Duty Ratio

Autorzy:

Wang, Y.
Foo, S. K.
He, Q.

Powiązania:

https://bibliotekanauki.pl/articles/226130.pdf

Data publikacji:

2015

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

Class E
power amplifier
numerical simulation

Opis:

Complementary to the conventional class-E topology, inverse class-E operation has several advantages over the class-E counterpart, such as lower peak switch voltage and smaller circuit inductance, which are attractive to high power RF design and MMIC implementation. This paper derives the closed-form design equations that can be used to synthesize the idealized operation of inverse class-E power amplifiers at any switch duty ratio. Calculation of the key design parameters, such as the maximum switch voltage and circuit components values, is elaborated and compared with the case of conventional class-E operation. Further, the theoretical analysis is confirmed and verified by numerical simulations performed on a 500mW, 2.4 GHz idealized inverse class-E power amplifier.

Źródło:

International Journal of Electronics and Telecommunications; 2015, 61, 3; 281-287
2300-1933

Pojawia się w:

International Journal of Electronics and Telecommunications

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 9.

Tytuł:

Interaction of Liquid Steel with Mould Flux in Continuous Casting Bloom Mould - Numerical Simulations and Industrial Experiences

Autorzy:

Cwudziński, A.
Jowsa, J.
Przegrałek, P.

Powiązania:

https://bibliotekanauki.pl/articles/353142.pdf

Data publikacji:

2016

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

liquid steel
numerical simulation
industrial experiences

Opis:

The device under examination is a mould of a capacity of 0.5 Mg and with inner cross-section of 280×400 mm. The virtual model of the facility under investigation was made using Gambit, DesignModeler and Meshing programs. Computer simulation of the liquid steel flow and mould flux behaviour in turbulent motion conditions was done using the Ansys-Fluent® computer program. On the basis of earlier researches the volume of fluid (VOF) model was applied. Based on computer simulations carried out, steel flow and flux behaviour fields and curves of flux mould entrainment concentration were obtained. The results obtained from numerical simulation were compared with the data obtained during bloom casting under industrial conditions. Based on the obtained information on the interaction of steel with mould flux, the region was determined, in which conditions likely to favour the entrainment of slag portions into the forming bloom exist.

Źródło:

Archives of Metallurgy and Materials; 2016, 61, 4; 2013-2020
1733-3490

Pojawia się w:

Archives of Metallurgy and Materials

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 10.

Tytuł:

Prediction of weld deformations by numerical methods - review

Autorzy:

Kozak, Janusz

Powiązania:

https://bibliotekanauki.pl/articles/32887011.pdf

Data publikacji:

2022

Wydawca:

Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa

Tematy:

welding distortion
shipbuilding welding
numerical simulation

Opis:

The welding process is the basic technique of joining in the shipbuilding industry. This method generates welding distortions that cause a lot of problems during the manufacturing process due to both the time and cost of straightening as well as their influence on later stages of production. Proper preparation of welding processes plays a growing role in the shipbuilding industry and the development of calculating tools is being observed. The paper presents a review and critical analysis of numerical methods for the assessment of welding distortion.

Źródło:

Polish Maritime Research; 2022, 1; 97-107
1233-2585

Pojawia się w:

Polish Maritime Research

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 11.

Tytuł:

Wstępna analiza zjawiska rykoszetowania wydłużonych penetratorów pocisków kinetycznych
Initial identification of the elongated penetrators ricochets

Autorzy:

Magier, M.

Powiązania:

https://bibliotekanauki.pl/articles/234705.pdf

Data publikacji:

2011

Wydawca:

Wojskowy Instytut Techniczny Uzbrojenia

Tematy:

rykoszetowanie
symulacje numeryczne
ricocheting
numerical simulation

Opis:

W pracy, na podstawie krytycznej analizy literatury problemu, przedstawiono wstępną charakterystykę zjawiska rykoszetowania i niszczenia wydłużonych pocisków podkalibrowych na pochylonych pancerzach. Określono wpływ kąta podejścia pocisku do płyty oraz konstrukcji pancerza na proces penetracji pociskiem podkalibrowym.
In this paper the problem of the elongated penetrators ricochets during penetration of the oblique plates are presented. Conclusions about the influence of the pitch angle and armour profile to penetration process were formulated basing on the critical review of the literature.

Źródło:

Problemy Techniki Uzbrojenia; 2011, R. 40, z. 117; 151-161
1230-3801

Pojawia się w:

Problemy Techniki Uzbrojenia

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 12.

Tytuł:

Simulation of damage process of containership’s side structure due to collision with a rock

Autorzy:

Porembski, G.
Kozak, J.

Powiązania:

https://bibliotekanauki.pl/articles/963393.pdf

Data publikacji:

2008

Wydawca:

Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa

Tematy:

collision
LS-DYNA
FEM
numerical simulation

Opis:

This paper presents methods and results of a simplified numerical simulation of collision process of containership’s side structure and a rock. Analysis of results of the modeling makes it possible to draw conclusions as to a character of the event as well as to estimate area and depth of damage caused by the penetrating rock, in order to select geometry of a filler and impermeable layer of 2nd protection barrier.

Źródło:

Polish Maritime Research; 2008, S 1; 18-21
1233-2585

Pojawia się w:

Polish Maritime Research

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 13.

Tytuł:

Landslide processes in a flysch massif - case study of the Kawiory landslide, Beskid Niski Mts. (Carpathians, Poland)

Autorzy:

Zabuski, L.
Wójcik, A.
Gil, E.
Mrozek, T.
Raczkowski, W.

Powiązania:

https://bibliotekanauki.pl/articles/2059216.pdf

Data publikacji:

2009

Wydawca:

Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy

Tematy:

Carpathian flysch
landslide
monitoring
numerical simulation

Opis:

Geological setting and precipitation triggers seem to be obvious parameters controlling landslides, but their relation to individual sliding processes has not been clear. We take on interdisciplinary approach (combining Earth science methods with an engineer ing-geotechnical approach) to examine sliding processes in the Kawiory landslide in the Polish Carpathians. Field parameters were obtained from inclinometer monitoring, meteorological records, piezometer data and geomechanical tests. Numerical simulation of the landslide development was performed, both for the reconstruction of the internal deformation phenomena on the slope and for approximate prediction of its future behaviour. An empirical formula describing the relationship between the depth of groundwater level (GWL) and precipitation is presented. The case study showed that for the ob served quasi-continuous creep, the depth and in particular the intensity of GWL fluctuations might be crucial.

Źródło:

Geological Quarterly; 2009, 53, 3; 317-332
1641-7291

Pojawia się w:

Geological Quarterly

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 14.

Tytuł:

Investigation of Sheet-Titanium Forming with Flexible Tool - Experiment and Simulation
Badanie kształtowania blach tytanowych z wykorzystaniem elastycznego narzędzia - doświadczenie i symulacja

Autorzy:

Adamus, J.
Lacki, P.

Powiązania:

https://bibliotekanauki.pl/articles/356127.pdf

Data publikacji:

2012

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

titanium sheet
flexible forming
numerical simulation

Opis:

In the paper the results of investigation of sheet-titanium forming with flexible tool are presented. Titanium alloy sheets belong to a group of materials which are very hard to deform at ambient temperature. To improve sheet formability forming technology using a semi-flexible tool was implemented. Experiments were carried out on a specially designed for this purpose device. Due to the application of a rubber pad the stress state similar to triaxial compression was produced in the deformed material. Such a stress state made it possible to obtain higher material deformation without risk of fracture. The numerical simulations were used for analysing the flexible forming process. The ADINA System basing on the Finite Element Method (FEM) was applied.
W artykule zaprezentowano wyniki badań procesu tłoczenia blach tytanowych za pomocą elastycznego narzędzia. Blachy ze stopów tytanu należą do grupy materiałów trudno odkształcalnych w temperaturze otoczenia. W celu zwiększenia tłoczności zastosowano technologie tłoczenia półelastycznym narzędziem. Doświadczenia przeprowadzono na stanowisku specjalnie zaprojektowanym w tym celu. Dzięki zastosowaniu gumowej wkładki w odkształcanym materiale wytworzony został stan naprężenia podobny do trójosiowego ściskania. Taki stan naprężenia umożliwił uzyskanie większych odkształceń materiału bez ryzyka pęknięcia. Do analizy procesu tłoczenia elastycznego wykorzystano symulacje numeryczne. Zastosowano program ADINA bazujący na Metodzie Elementów Skończonych (MES).

Źródło:

Archives of Metallurgy and Materials; 2012, 57, 4; 1247-1252
1733-3490

Pojawia się w:

Archives of Metallurgy and Materials

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 15.

Tytuł:

Review of potential advantages and pitfalls of numerical simulation of self-excited vibrations

Autorzy:

Jemielniak, K.
Wypysiński, R.

Powiązania:

https://bibliotekanauki.pl/articles/99795.pdf

Data publikacji:

2013

Wydawca:

Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych

Tematy:

numerical simulation
nonlinear chatter
cutting dynamic

Opis:

Machining stability is one of the most important factors influencing the geometrical and dimensional accuracy of the machined parts. Regenerative chatter is a major limitation to the productivity and quality of machining operations due to poor surface finish and faster tool wear. In general there are two methods of stability analysis: solution of differential equations of the system in frequency domain or numerical simulation in time domain. Fast and easy calculations in the frequency domain are possible using a simplified linear model of cutting process. Important limitations of these methods are difficult or impossible considering of changes of dynamic cutting force coefficients and dynamic characteristic of a process. Numerical simulation has not these limitations and regards many specific phenomena of the cutting processes, therefore it is often used in the stability analysis. The paper presents main advantages of numerical simulation, which differentiates it from the analytical solutions, as well as some inevitable difficulties and limitations.

Źródło:

Journal of Machine Engineering; 2013, 13, 3; 77-90
1895-7595
2391-8071

Pojawia się w:

Journal of Machine Engineering

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 16.

Tytuł:

Numerical Simulation of Self-Excited Vibrations Under Variable Cutting Conditions

Autorzy:

Bąk, P. A.
Jemielniak, K.

Powiązania:

https://bibliotekanauki.pl/articles/99477.pdf

Data publikacji:

2015

Wydawca:

Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych

Tematy:

self-excited vibration
numerical simulation
virtual machining

Opis:

A self-excited vibrations are one of the most important constraints to the performance and quality of machining part and it is affecting its dimensions and geometrical accuracy. Machining stability can be evaluated by different analytical and numerical methods. The paper presents utilization of numerical simulation of non-linear chatter in the time domain in stability analysis of machining process. Vibrations and cutting forces are an output from numerical simulation. In order to perform chatter recognition during excessive vibrations an automatic chatter detection is implemented in machining simulation. By combining all the above in one and enabling G-code reading, a tool for numerical simulation and validation of entire machining operation was created which is a subject of this paper.

Źródło:

Journal of Machine Engineering; 2015, 15, 1; 36-45
1895-7595
2391-8071

Pojawia się w:

Journal of Machine Engineering

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 17.

Tytuł:

Experimental research and numerical analysis of 9 mm Parabellum projectile penetration of ultra-high molecular weight polyethylene layers
Badania eksperymentalne i analiza numeryczna penetracji 9 mm pociskiem Parabellum warstw polietylenowych o ultra-wysokiej masie cząsteczkowej

Autorzy:

Wiśniewski, A.
Pacek, D.

Powiązania:

https://bibliotekanauki.pl/articles/235372.pdf

Data publikacji:

2013

Wydawca:

Wojskowy Instytut Techniczny Uzbrojenia

Tematy:

UHMWPE
numerical simulation
AUTODYN
symulacja numeryczna
Autodyn

Opis:

The paper presents results of experimental research and numerical analysis of the 9 mm Parabellum projectile (brass jacket, lead core) impact (impact velocity Vi = 365 m/s) into layers of the nonwoven polyethylene Dyneema®SB71 (100x100 mm) placed on the backing material. 3D numerical simulations with the use of the Ansys Autodyn v14 program were made. On the basis of the literature and own results of the weight drop test into ballistic plasticine (backface signature BFS = 18-24 mm) conforming to experimental tests numerical model of backing material was made. As a boundary condition in the numerical simulations of projectile impact into Dyneema®SB71 layers it was assumed loading of the tightening belt with 25 N force. In difference to experimental results in numerical simulations the front part of the jacket torn off and the core material flow outside the jacket and there were no perforated layers.
W artykule przedstawiono wyniki badań ostrzałem oraz analiz numerycznych uderzenia pocisku 9 mm Parabellum (płaszcz mosiężny, rdzeń. ołowiany, prędkość uderzenia Vi = 365 m/s) w warstwy nietkanego wyrobu polietylenowego Dyneema®SB71 (100x100 mm) umieszczonego na podłożu balistycznym. Symulacje numeryczne 3D zrealizowano w programie do analiz dynamicznych Ansys Autodyn v14. W oparciu o dane literaturowe oraz własne wyniki zrzutu swobodnego ciężarka na plastelinę balistyczną (głębokość deformacji podłoża BFS = 18-24 mm) opracowano zgodny z wynikami badań eksperymentalnych model numeryczny podłoża balistycznego. Jako warunek brzegowy w symulacji uderzenia pocisku w warstwy Dyneema'y®SB71 przyjęto obciążenie paska dociskającego siłą 25 N. W odróżnieniu od badań ostrzałem w symulacji numerycznej oderwała się przednia część płaszcza pocisku oraz nie nastąpiło przebicie żadnej z warstw wyrobu polietylenowego Dyneema®SB71.

Źródło:

Problemy Techniki Uzbrojenia; 2013, 42, 127; 55-64
1230-3801

Pojawia się w:

Problemy Techniki Uzbrojenia

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 18.

Tytuł:

Numerical testing of landing gear system for different drop velocities

Autorzy:

Krasoń, W.
Małachowski, J.

Powiązania:

https://bibliotekanauki.pl/articles/245668.pdf

Data publikacji:

2009

Wydawca:

Instytut Techniczny Wojsk Lotniczych

Tematy:

landing gear
numerical simulation
drop velocities
touchdown

Opis:

The FEM model of the landing gear was developed to determine efforts of individual structural members while simulating the landing-gear drop, and to investigate how the energy of such a system changes; also, to find what kinds of deformations occur in individual components, and to investigate into the effectiveness of the damping system. In the developed numerical model of the landing gear account was taken also of the support-wheel-related subassembly, which includes such elements as: the wheel pin, the wheel rim, and the tyre. All parts of this subassembly, belt in the tyre excluded, were represented with the flexible hexagonal elements. results of numerical analyses for some selected drop tests and results from experiments carried out on a real landing gear confirm high quality of results gained from the dynamic simulation in the model of a complete landing-gear configuration. The advantage of the presented numerical method is applicability there of to landing gear testing for the very wide range of drop velocities, what is impossible to be performed with other methods, including experimental testing work. Paper show the geometric model of the main landing gear, a discrete model with the shock-absorber model included, the fringe of the landing gear deformation at the flnal stage of touchdown phase respectively from experimental and numerical tests and the maps ofmaximum principal stresses and how they change within the area of the welded joint that connects the upper and lower levers of the main landing gear.

Źródło:

Journal of KONES; 2009, 16, 4; 241-246
1231-4005
2354-0133

Pojawia się w:

Journal of KONES

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 19.

Tytuł:

Optimization of a nonconventional engine evaporator

Autorzy:

Kovalčik, A.
Toporcer, E.

Powiązania:

https://bibliotekanauki.pl/articles/246938.pdf

Data publikacji:

2010

Wydawca:

Instytut Techniczny Wojsk Lotniczych

Tematy:

nonconventional engine
evaporator
numerical simulation
mesh
flow

Opis:

The papers deal with the optimization of the evaporator of a nonconventional combustion engine. Lithium bromide liquid (LiBr - an alternative cooling medium) flows in a cooling circuit of a nonconventional energetic unit. The solved energetic system is defined in the area of trigeneration systems. The mentioned system is a source of electric energy, cold and heat too. The space geometrical model corresponding to the geometry of the original evaporator is created in the CAD (Computer Aided Design) software CATIA. Only one half of the evaporator is created because of the decrease in the demand on the computational means. This CAD model is then imported into the preprocessor Gambit. The imported model is repaired and a suitable mesh is then created. The last step is the definition of the types of boundary conditions. The completed computational mesh is then exported from Gambit and imported into the CFD (Computational Fluid Dynamics) software Fluent. Fluent is used for the numerical simulation of the cooling medium flow in an evaporator. The simulation shows the filling of the evaporator cone, the time when the cooling medium starts to pour through the edge of the evaporator cone, the filling of the evaporator ring and finally also the fact that the off-take is able to take away the needed amount of cooling liquid from the evaporator.

Źródło:

Journal of KONES; 2010, 17, 2; 217-223
1231-4005
2354-0133

Pojawia się w:

Journal of KONES

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 20.

Tytuł:

Numerical simulation of blood flow and cholesterol distribution for middle cerebral artery with coarctation

Autorzy:

Naito, M.
Mizoguchi, K.
Takagi, Y.
Okano, Y.

Powiązania:

https://bibliotekanauki.pl/articles/385258.pdf

Data publikacji:

2009

Wydawca:

Sieć Badawcza Łukasiewicz - Przemysłowy Instytut Automatyki i Pomiarów

Tematy:

numerical simulation
blood flow
coarctation
cholesterol distribution

Opis:

In order to understand of coarctation growth mechanism in a blood tube, numerical analysis for blood flow and cholesterol distribution in a blood tube was carried out. Numerical results showed that back flow existed behind the coarctation, and it was found that high blood pressure (HBP), and nonelastic conditions increased the cholesterol concentration behind the coarctation.

Źródło:

Journal of Automation Mobile Robotics and Intelligent Systems; 2009, 3, 4; 179-183
1897-8649
2080-2145

Pojawia się w:

Journal of Automation Mobile Robotics and Intelligent Systems

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 21.

Tytuł:

Numerical simulation of tonal and broadband hydrodynamic noises of noncavitating underwater propeller

Autorzy:

Kheradmand, S.
Rahrovi, A.
Mousavi, B.

Powiązania:

https://bibliotekanauki.pl/articles/259022.pdf

Data publikacji:

2014

Wydawca:

Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa

Tematy:

Numerical Simulation
tonal
broadband
Hydrodynamic Noise
Propeller

Opis:

The objective of the study was to carry out numerical simulation of the hydrodynamic noise generated by the flow around a non-cavitating underwater propeller. To achieve this goal, hydrodynamic simulation of flow around the propeller was initially done. The unsteady 3-D flow was modelled numerically along with the LES turbulence model. The hydrodynamic parameters calculated for different advance coefficients are visibly in line with the previous experimental works. The turbulent quantities of the hydrodynamic study and the FWH model were used to find spectral distributions of flow noise for different advance coefficients. The results of the acoustic investigation were compared against other numerical results. An array of 100 hydrophones was used to find the directional distribution of the noise around the propeller. The obtained results indicate that, for different advance coefficients, the highest intensity of the noise recorded by different receivers around the propeller occurs in BPF. Furthermore, it has been found that the noise is directionally as well as intensively distributed around the propeller. Noise distributions of noise are presented and discussed for different regimes of propeller rotation. The analysis of the expanded spectrum (broadband analysis) of noise on the propellers has also been done and the contribution of all parts of the propeller to hydrodynamic noise generation are presented.

Źródło:

Polish Maritime Research; 2014, 3; 46-53
1233-2585

Pojawia się w:

Polish Maritime Research

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 22.

Tytuł:

Weapon Barrel and Its Additional Accessories

Autorzy:

Lisý, P.
Štiavnický, M.

Powiązania:

https://bibliotekanauki.pl/articles/403953.pdf

Data publikacji:

2014

Wydawca:

Wojskowa Akademia Techniczna im. Jarosława Dąbrowskiego

Tematy:

assault rifle
weapon barrel vibration
numerical simulation

Opis:

This paper deals with any additional accessories has on a weapon barrel during the initial shot this was done by numerical simulation. This means, that in this paper the influence that the configuration of the assault rifle has on its accuracy is solved. Moreover the weapons muzzle position during the firing of a shot without the influence of temperature or wear of the barrel is solved. The weapon barrel and bullet are both modelled using LS-DYNA software. The barrel is steel and is ideally straight without any structural or manufactured deviations. The bullet is NATO standard 5.56 mm calibre which is consists of a brass jacket and a lead core. The bullets interaction with the barrel during a shot is given by pressured gunpowder gasses both in the barrel and the bullets base whereby it gives the bullet its forward velocity. At the initial stages of the bullets flight it has to overcome its engraving into grooves of the barrel. Both applied pressure and the movement of the bullet along the barrel gives rise to barrel vibration. This barrel vibration has an influence on its muzzle position when the bullet leaves the muzzle. Furthermore, both additional accessories and various conditions of the barrels grip onto the weapons casing have additional influences on the muzzles position when the bullet leaves the muzzle, thus having a great influence on precision.

Źródło:

Problemy Mechatroniki : uzbrojenie, lotnictwo, inżynieria bezpieczeństwa; 2014, 5, 1 (15); 9-24
2081-5891

Pojawia się w:

Problemy Mechatroniki : uzbrojenie, lotnictwo, inżynieria bezpieczeństwa

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 23.

Tytuł:

Application of Thermo-Bimaterial Effect in Designing of Snap-Fit Joints

Autorzy:

Golewski, P.
Sadowski, T.

Powiązania:

https://bibliotekanauki.pl/articles/351310.pdf

Data publikacji:

2019

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

snap fit joint
numerical simulation
bi-material

Opis:

Snap-fit connections have been used for many years in various fields of technology and everyday objects. They often have complex shapes, which is allowed by the processing technology of the polymers from which they are made, but they are not designed to carry loads. Changing the material to a metal or fiber composite allows these types of joints to be used as replacements for rivets or screws, but there are problems with the closing technique – an increase in closing force due to the large Young’s modulus ofthese materials relative to polymers without reinforcement. One of the methods to solve this problem may be the use of a thermo-bimetallic effect consisting in heating both or one of the connection parts to the appropriate temperature. This kind of treatment results in deflection of the beam of the clip (Fig. 1), followed by assembly with zero force or less in relation to the case without heating.The paper presents the results of numerical simulations for the connection in which the beam of the clip consisted of two materials: (1) a fiber composite designed to carry loads, (2) thin metal layer tied with the composite and designed to create a thermo-bimetallic effect. In the case of this solution, the main parameter is the difference in coefficients of linear thermal expansion of both materials. The paper presents results for two cases of connection work: closing and opening. The calculations were carried out in the Abaqus/Standard solver using thermal-displacement steps.

Źródło:

Archives of Metallurgy and Materials; 2019, 64, 3; 1095-1100
1733-3490

Pojawia się w:

Archives of Metallurgy and Materials

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 24.

Tytuł:

Effect of Filter Thickness on Reoxidation and Mechanical Properties of Aluminium Alloy AlSi7Mg0.3

Autorzy:

Bruna, M.
Remišová, A.
Sládek, A.

Powiązania:

https://bibliotekanauki.pl/articles/352359.pdf

Data publikacji:

2019

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

bifilm
numerical simulation
reoxidation
mechanical properties
filtration

Opis:

The melt cleaning is an important aspect in the production of high-quality aluminum castings. Specifically inclusions within the melt and an excessively high hydrogen content lead to defects and undesired porosity in the castings. Although it is possible to reduce the amount of hydrogen and oxidic inclusions by purge gas treatment and the use of melting salts, it is impossible toremove oxides (bifilms) created during filling of gating system. Paper deals with the effects of melt quality and the placement of a filter in the filling system on Al-7%Si-Mg alloy mechanical properties. Three different filters were used: (a) rectangular ceramic pressed filter with 3 mm thickness (b) cubical pressed ceramic filter with thickness 10 mm (c) cubical pressed ceramic filter with thickness 22 mm. The results showed that the highest tensile strength values were obtained from the filter with thickness of 22 mm. Numerical simulation analysis of the filling process showed that velocity reduction by filter is the major phenomenon affecting the mechanical properties. Another evaluated aspect during experiments was capability of filters to retain old bifilms. For this purpose multiply remelted alloy was prepared and analyzed. Results showed that filter efficiency increases with decreasing melt quality as a result of possibility to retain "old” bifilms better than small and thin "new” bifilms.

Źródło:

Archives of Metallurgy and Materials; 2019, 64, 3; 1100-1106
1733-3490

Pojawia się w:

Archives of Metallurgy and Materials

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 25.

Tytuł:

Effect of spiral vanes width on the separation performance of a hydrocyclone

Autorzy:

Liu, Peikun
Wang, Xiaoguo
Jiang, Lanyue
Zhang, Yuekan
Yang, Xinghua
Li, Xiaoyu
Wang, Hui

Powiązania:

https://bibliotekanauki.pl/articles/27323656.pdf

Data publikacji:

2023

Wydawca:

Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej

Tematy:

hydrocyclone
vane width
numerical simulation
separation performance

Opis:

Aiming at the problem of “entrainment fine particles in underflow” of hydrocyclone in grinding and classification process, a hydrocyclone with spiral vanes (the SV hydrocyclone) was proposed. The CFD techniques were used to study the pressure field, velocity field, turbulence field, particle field and classification efficiency of hydrocyclones with spiral vanes of different widths. The results show that the pressure drop, axial velocity, tangential velocity, turbulence intensity of SV hydrocyclone are reduced in different degrees compared with conventional hydrocyclone, and the reduction becomes more obvious with the increase of vane width. In the case of a vane width of 0.04D, the underflow recovery rate of 5μm and 10μm fine particles was reduced by 16.2% and 15.7%. The selection of spiral vanes with small widths is beneficial to improve the separation accuracy of fine particles and reduce the cut particle size.

Źródło:

Physicochemical Problems of Mineral Processing; 2023, 59, 6; art. no. 173563
1643-1049
2084-4735

Pojawia się w:

Physicochemical Problems of Mineral Processing

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 26.

Tytuł:

Experimental and numerical analysis of vortex generators designed for utility vehicles

Autorzy:

Chidambaram, Ramesh Kumar
Kanna, Rajesh
Gopal, Poomanandan
Arumugam, Senthil Kumar

Powiązania:

https://bibliotekanauki.pl/articles/27312222.pdf

Data publikacji:

2023

Wydawca:

Polska Akademia Nauk. Czasopisma i Monografie PAN

Tematy:

vortex generator
pressure coefficient
numerical simulation
drag force

Opis:

The main goal of today’s car designers is to minimize fuel consumption in all possible ways at the same time maintaining the vehicle’s performance as usual. The goal of this work is to study the effect of adding a vortex generator (VG) on the aerodynamics of the vehicle and fuel economy. Both theoretical and experimental works were carried out and the outcomes of the numerical simulations are contrasted with those of the experimental results. A utility vehicle model with a scale ratio of 1:15 was used as a test model. Experimental research has been done on the fluctuation of the coefficient of pressure, dynamic pressure, and coefficients of lift and drag with and without VG on the roof of a utility vehicle. The delta-shaped VG was put to the test both numerically and experimentally. At a velocity of 2.42 m/s, it is observed that the addition of VG can raise the pressure coefficient by about 17%. When compared to the vehicle model without vortex generators, the velocity profile of the ccomputational fluid dynamics analysis shows that at the back end of the vehicle, the wake has been minimized with VG.

Źródło:

Archives of Thermodynamics; 2023, 44, 3; 217--240
1231-0956
2083-6023

Pojawia się w:

Archives of Thermodynamics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 27.

Tytuł:

Modeling and optimization of the YAG:Yb microchip laser passively Q-switched by YAG:Cr absorber

Autorzy:

Buryy, O
Ubizskii, S

Powiązania:

https://bibliotekanauki.pl/articles/175041.pdf

Data publikacji:

2014

Wydawca:

Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej

Tematy:

Yb:YAG crystal
microlaser
Q-switching
numerical simulation

Opis:

Based on analytical and numerical solutions of the rate equations system and the heat conductivity equation, the model of the quasi-three-level passively Q-switched YAG:Yb/YAG:Cr microchip laser is developed. The obtained results are used for its optimization, i.e., for the determination of the output mirror reflectivity, the pumping beam radius, the thickness of the absorber and the phototropic centers concentration maximizing the energy in the laser pulse. The influence of the thermal load on the spatial parameters of the laser beam is also determined.

Źródło:

Optica Applicata; 2014, 44, 4; 621-636
0078-5466
1899-7015

Pojawia się w:

Optica Applicata

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 28.

Tytuł:

Modelowanie matematyczne kinetyki suszenia okresowego pszenicy w układzie fluidalnym
Mathematical modelling of periodic drying kinetics of wheat in a lluidized bed system

Autorzy:

Ciesielczyk, W.
Kamińska-Pękala, A.

Powiązania:

https://bibliotekanauki.pl/articles/2073192.pdf

Data publikacji:

2016

Wydawca:

Stowarzyszenie Inżynierów i Techników Mechaników Polskich

Tematy:

suszenie
fluidyzacja
modelowanie matematyczne
drying
fluidization
numerical simulation

Opis:

Przedstawiono ujęcie ilościowe kinetyki suszenia pszenicy. Zaproponowane równania ujmują zarówno ruch masy i ciepła między analizowanymi strefami, jak i między ciałem stałym, a gazem. W pracy zastosowano model dwustrefowy, wyróżniający strefę emulsji i strefę pęcherzy. Wyniki przewidywań teoretycznych pochodzących z obliczeń symulacyjnych zostały zweryfikowane przez porównanie z danymi doświadczalnymi otrzymanymi z użyciem suszarki fluidyzacyjnej o średnicy 0,150 m. Suszarka wyposażona była w oryginalne rozwiązanie konstrukcji dystrybutora gazu zapewniającego efektywną fluidyzację materiałów zaliczanych do grupy D wg klasyfikacji Geldarta. W części pracy dotyczącej pół-empirycznych metod analizy suszenia wykazano możliwość wykorzystania w obliczeniach procesowych koncepcji tzw. uogólnionej krzywej suszenia, co pozwala na znaczne ograniczenie zakresu badań eksperymentalnych niezbędnych do projektowania procesowego.
Quantification of drying kinetics of wheat is presented. The proposed equations describe the motion of heat and mass transfer between the analyzed zones, and between solid and gas phases. In the study a two-zone model comprising the distinctive emulsion and bubbles zones was used. The results of theoretical predictions obtained in simulations were validated by comparison with the experimental data collected in the fluidized bed dryer of a diameter equal to 0.150 meters. The dryer was equipped with a specially design gas distributor enabling efficient fluidization of materials belonging to the group D in Geldart classification. In the part of this work dealing with semi-empirical methods of drying analysis the possibility of applying a so-called concept of generalized drying curve in process calculations was demonstrated. This approach allows one to restrict significantly a scope of experimental research necessary in process design.

Źródło:

Inżynieria i Aparatura Chemiczna; 2016, 5; 175--177
0368-0827

Pojawia się w:

Inżynieria i Aparatura Chemiczna

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 29.

Tytuł:

Numerical study of a cracked pipeline under internal pressure

Autorzy:

Abderraouf, Khireche
Zohra, Labed

Powiązania:

https://bibliotekanauki.pl/articles/2065776.pdf

Data publikacji:

2020

Wydawca:

Politechnika Poznańska. Wydawnictwo Politechniki Poznańskiej

Tematy:

steel
pipelines
internal pressure
crack
thickness
numerical simulation

Opis:

In the industrial sectors, pipelines have been used as the most economical and safe means of transporting oil and gas (Pipelines). However, the number of accidents has increased considerably as their use has increased. As a result of the operating load and the pressure used, the thickness of the tube must be increased and the mechanical characteristics improved. This approach was applied to predict the growth of crack effect in samples of two pipelines at given thicknesses and pressures. We created cracks with deferential dimensions in both API X80 steel pipelines, with an application of deferential internal pressures. For the simulations, we used the code ANSYS.

Źródło:

Archives of Mechanical Technology and Materials; 2020, 40; 30--33
2450-9469

Pojawia się w:

Archives of Mechanical Technology and Materials

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 30.

Tytuł:

Numerical Simulation Studies on the Process of Machining of Shafts with Low Rigidity

Autorzy:

Świć, A.
Gola, A.

Powiązania:

https://bibliotekanauki.pl/articles/117946.pdf

Data publikacji:

2016

Wydawca:

Polskie Towarzystwo Promocji Wiedzy

Tematy:

turning
shaft with low rigidity
numerical simulation studies

Opis:

The paper presents a computer program developed for the determination of the basic dynamic characteristics of the process of machining, numerical simulations of the dynamic system of the process of machining, and graphic presentations of the numerical simulations performed. Results of simulations of the runs of time and frequency characteristics of the process of machining with variable machining parameters are presented. High goodness-of-fit of the model with the actual process of turning was achieved.

Źródło:

Applied Computer Science; 2016, 12, 2; 42-53
1895-3735

Pojawia się w:

Applied Computer Science

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 31.

Tytuł:

Improved method for simulating transients of turbulent pipe flow

Autorzy:

Zarzycki, Z.
Kudźma, S.
Urbanowicz, K.

Powiązania:

https://bibliotekanauki.pl/articles/280935.pdf

Data publikacji:

2011

Wydawca:

Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej

Tematy:

unsteady pipe flow
transients
waterhammer
efficient numerical simulation

Opis:

The paper presents the problem of modelling and simulation of transients during turbulent fluid flow in hydraulic pipes. The instantaneous wall shear stress on a pipe wall is presented in the form of integral convolution of a weighting function and local acceleration of the liquid. This weighting function depends on the dimensionless time and Reynolds number. Its original, very complicated mathematical structure is approximated to a simpler form which is useful for practical engineering calculations. The paper presents an efficient way to solve the integral convolution based on the method given by Trikha (1975) for laminar flow. An application of an improved method with the use of the Method of Characteristic for the case of unsteady flow (water hammer) is presented. This method is characterised by high efficiency compared to traditional numerical schemes.
Artykuł przedstawia zagadnienie modelowania i symulacji przebiegów przejściowych podczas turbulentnego przepływu cieczy w przewodach ciśnieniowych. Chwilowe naprężenie styczne na ściance przewodu przedstawiono w postaci całki splotowej z funkcji wagi i przyspieszenia cieczy. Funkcja wagi dla naprężenia stycznego na ściance przewodu zależy od czasu bezwymiarowego i liczby Reynoldsa. Ma ona zawiłą postać matematyczną, dlatego aproksymowano ją do prostszej postaci, przydatnej do praktycznych obliczeń inżynierskich. Przedstawiono efektywny sposób rozwiązania całki splotowej, opierając się na metodzie podanej przez Trikha (1975) dla przepływu laminarnego. Podano zastosowanie ulepszonej metody symulacji naprężenia stycznego do metody charakterystyk podczas uderzenia hydraulicznego. Charakteryzuje się ona dużą efektywnością w stosunku do metody tradycyjnej.

Źródło:

Journal of Theoretical and Applied Mechanics; 2011, 49, 1; 135-158
1429-2955

Pojawia się w:

Journal of Theoretical and Applied Mechanics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 32.

Tytuł:

Numerical modelling of bio-heat transfer using the boundary element method
Modelowanie numeryczne przepływu bio-ciepła za pomocą metody elementów brzegowych

Autorzy:

Majchrzak, E.

Powiązania:

https://bibliotekanauki.pl/articles/281250.pdf

Data publikacji:

1998

Wydawca:

Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej

Tematy:

boundary element method
bio-heat transfer
numerical simulation

Opis:

Numerical models of heat transfer processes proceeding in a biological tissue subjected to a strong external thermal interaction are discussed. In this case one can consider diametrically different phenomena; such as burns resulting from thermal contact of the skin with an external heat source, or the freezing process of biological tissue used in cryosurgery. From the mathematical point of view these processes belong to the group of boundary-initial problems described by the diffusion equation and adequate boundary-initial conditions. At the stage of numerical realization the boundary element method can be applied and such an approach is discussed in this paper.
W pracy przedstawiono opisy matematyczne i modele numeryczne procesów cieplnych zachodzących w tkance biologicznej poddanej silnym termicznym oddziaływaniom zewnętrznym. Można tu rozpatrywać skrajnie różne zjawiska, takie jak oparzenia wynikające z kontaktu skóry z zewnętrznym źródłem ciepła, lub też proces zamrażania tkanki w czasie zabiegu kriochirurgicznego. Z matematycznego punktu widzenia procesy te należą do grupy zadań brzegowo-początkowych opisanych równaniami dyfuzji i odpowiednimi warunkami jednoznaczności. Na etapie realizacji numerycznej można wykorzystać metodę elementów brzegowych i takie właśnie podejście jest prezentowane w niniejszej pracy.

Źródło:

Journal of Theoretical and Applied Mechanics; 1998, 2; 437-455
1429-2955

Pojawia się w:

Journal of Theoretical and Applied Mechanics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 33.

Tytuł:

Numerical investigation of the inner flow in a centrifugal pump at the shut-off condition

Autorzy:

Liu, H.
Wu, X
Tan, M.

Powiązania:

https://bibliotekanauki.pl/articles/281524.pdf

Data publikacji:

2013

Wydawca:

Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej

Tematy:

centrifugal pump
numerical simulation
shut-off condition
PIV

Opis:

The unsteady flow fields in a centrifugal pump at the shut-off condition (SOC) are simulated by the Unsteady Reynolds Averaged Navier-Stokes (URANS) approach. To improve simulation accuracy and assign the boundary condition, special 3D models are made. Three-dimensional URANS equations are solved on high-quality unstructured grids with the shear stress transport turbulence model by using the computational fluid dynamics (CFD) code CFX-11.0. Furthermore, the numerical simulation results are validated by particle image velocimetry (PIV) measurements. The main goal of the study is, on one hand, the validation of the numerical procedure proposed, and on the other hand, the detailed analysis of the unsteady inner flow field distribution and pressure fluctuation in the centrifugal pump at SOC. In addition, the head of the pump at SOC is predicted based on CFD results. The flow analysis indicates that there exists two eddies in each impeller flow passage, and the velocity at the volute diffusion part is very low. The amplitudes of pressure fluctuation at ƒr (impeller rotation frequency) and 3ƒr dominate in the impeller, while the pressure fluctuation at ƒb (blade passing frequency) is dominant in the volute.

Źródło:

Journal of Theoretical and Applied Mechanics; 2013, 51, 3; 649-660
1429-2955

Pojawia się w:

Journal of Theoretical and Applied Mechanics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 34.

Tytuł:

Wpływ parametrów ekranu wiatrowego na kształtowanie przepływu w strefie recyrkulacji
The influence of wind screen parameters on wind flow conditions in recirculation zone

Autorzy:

Klemm, K

Powiązania:

https://bibliotekanauki.pl/articles/362812.pdf

Data publikacji:

2010

Wydawca:

Instytut Fizyki Budowli Katarzyna i Piotr Klemm

Tematy:

osłona wiatrowa
symulacja numeryczna
wind screen
numerical simulation

Opis:

W pracy przedstawione zostały wyniki analiz symulacyjnych przepływu powietrza w strefie recyrkulacji między ekranem wiatrowym a budynkiem. Odległość między ekranem a budynkiem była stała, podobnie jak wymiary samego budynku zmianie podlegała wysokość ekranu oraz jego porowatość. W celu określenia warunków wiatrowych w strefie między ekranem a budynkiem dokonano analizy prędkości w dziesięciu równo oddalonych od siebie punktach, wzdłuż 6 linii usytuowanych prostopadle i równolegle do rozpatrywanego układu.
The paper presents results of numerical simulation of wind flow in recirculation zone located between wind screen and a building. Distance between the screen and the building was constant, as the building's dimension. The height and porosity of the screen were variable. In order to determine wind conditions in the analysed area a number of simulations were carried out in ten equally spaced points along six lines situated perpendicularly and in parallel to the analysed complex.

Źródło:

Fizyka Budowli w Teorii i Praktyce; 2010, T. 5, nr 4, 4; 15-21
1734-4891

Pojawia się w:

Fizyka Budowli w Teorii i Praktyce

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 35.

Tytuł:

Algorytm sterowania aktywnego układu dźwiękochłonno-izolacyjnego z wykorzystaniem sieci neuronowej i algorytmu genetycznego
A smart active structural acoustic control utilizing neural networks and genetic algorithm

Autorzy:

Krukowicz, T.
Morzyński, L.

Powiązania:

https://bibliotekanauki.pl/articles/181325.pdf

Data publikacji:

2012

Wydawca:

Centralny Instytut Ochrony Pracy

Tematy:

wibroakustyka
hałas
symulacja numeryczna
vibroacoustic
noise
numerical simulation

Opis:

W artykule przedstawiono algorytm sterowania aktywnym ustrojem dźwiękochłonno-izolacyjnym wykorzystującym materiały inteligentne. Algorytm działa w oparciu o sieci neuronowe i algorytm genetyczny. Opis algorytmu poprzedzono krótkim omówieniem materiałów inteligentnych wykorzystywanych do budowy aktywnych układów dźwiękochłonno-izolacyjnych z uwzględnieniem zjawisk degradujących skuteczność omawianych układów wykorzystujących klasyczne techniki sterowania. Przedstawiono wyniki symulacji numerycznych działania aktywnego układu dźwiękochłonno-izolacyjnego. Rezultaty przeprowadzonych symulacji pozwalają stwierdzić, że opracowany algorytm pozwoli na konstruowanie aktywnych ustrojów dźwiękochłonno-izolacyjnych o dużej efektywności.
In this paper a algorithm for smart active structural acoustic control systems is presented.The algorithm utilizes neural networks and a genetic algorithm. Derivation of the algorithm is preceded by a brief overview about smart materials and smart structures including the description of the phenomena that may decrease efficiency control of the classic approach over smart active structural acoustic systems. Examples of numerical simulations of performance smart active structural acoustic control systems are presented which show that by using proposed algorithm in smart active structural acoustic control systems high noise reduction can be assured.

Źródło:

Bezpieczeństwo Pracy : nauka i praktyka; 2012, 9; 27-29
0137-7043

Pojawia się w:

Bezpieczeństwo Pracy : nauka i praktyka

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 36.

Tytuł:

Numeryczny model wlewka ciągłego i jego zastosowanie do symulacji procesu ciągłego odlewania wlewków kwadratowych ze stali konstrukcyjnej
Numerical model of continuously cast strand and its application for simulation of continuous casting of structural steel blooms

Autorzy:

Burbelko, A.
Kapturkiewicz, W.
Kudliński, Z.
Pieprzyca, J.

Powiązania:

https://bibliotekanauki.pl/articles/182404.pdf

Data publikacji:

2012

Wydawca:

Sieć Badawcza Łukasiewicz - Instytut Metalurgii Żelaza im. Stanisława Staszica

Tematy:

odlewanie ciągłe
symulacja numeryczna
continuous casting
numerical simulation

Opis:

Przedstawiono założenia wyjściowe i wyniki modelowania krzepnięcia wlewków stalowych o przekroju kwadratowym 160×160 mm odlewanych ze stali gatunku B1 w łukowej instalacji COS. Przeprowadzono modelowanie krzepnięcia wlewków. W modelowaniu wykorzystano oprogramowanie ProCAST (ESI Group). Wykazano możliwość prognozowania pola temperatury we wlewku oraz profilu przestrzennego strefy ciekłej i dwufazowej (ciekło-stałej).
The input assumptions and simulation results for solidification modelling of 160×160 mm blooms produced from low alloy structural steel in the bow - type continuous casting machine are presented. The modelling of solidification was carried out by means of ProCAST software (ESI Group). The abilities of forecasting the temperature field in the cast strand as well as space distribution of liquid and two-phase (liquid and solid) fraction are shown.

Źródło:

Prace Instytutu Metalurgii Żelaza; 2012, T. 64, nr 1, 1; 41-47
0137-9941

Pojawia się w:

Prace Instytutu Metalurgii Żelaza

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 37.

Tytuł:

Numerical simulation of the molten steel flow in the tundish of CSC machine
Symulacja numeryczna przepływu ciekłej stali w kadzi pośredniej urządzenia COS

Autorzy:

Sowa, L.
Bokota, A.

Powiązania:

https://bibliotekanauki.pl/articles/356209.pdf

Data publikacji:

2012

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

continuous casting
tundish
molten metal flow
numerical simulation

Opis:

The mathematical and numerical simulation model of the liquid steel flow in a tundish is presented in this paper. The problem was treated as a complex one. The velocity fields are obtained by solving the momentum equations and the continuity equation, whereas the thermal fields are calculated by solving the conduction equation with the convection term. One takes into consideration in the mathematical model the changes of thermophysical parameters depending on the temperature. The problem was solved by the finite element method. The one-strand slab tundish is used to casting slabs. The internal work space of the tundish was modified by flow control devices. The first device was a striker pad situated in the pouring tundish zone. The second device was a baffle with three holes. The main purpose of using these was to put barriers in the steel flow path as well as give directional metal flow upwards which facilitated inclusion floatation. The visualization of interaction of flow control devices on hydrodynamic conditions was received from numerical simulations. As a result of the computations carried out, the liquid steel flow and steel temperature fields were obtained. The influences of the tundish modifications on the velocity fields in liquid phase of the steel were estimated, because these have essential an influence on high-quality of a continuous steel cast slab.
W pracy przedstawiono model matematyczny i numeryczny przepływu ciekłej stali w kadzi pośredniej urządzenia ciagłego odlewania. Zadanie potraktowano kompleksowo. Pola prędkości otrzymano z rozwiązania równań Naviera-Stokesa i równania ciagłości przepływu, natomiast pola temperatury z rozwiązania równania przewodnictwa z członem konwekcyjnym. Uwzględniono zmianę parametrów termofizycznych od temperatury. Problem rozwiązano metodą elementów skończonych. Do rozważań wybrano jednowylewowa kadź pośrednia przeznaczona do odlewania wlewków płaskich. Przestrzeń robocza kadzi pośredniej została zmodyfikowana i zabudowana urządzeniami sterującymi przepływem ciekłej stali. Pierwszym urządzeniem był amortyzator kadzi pośredniej umieszczony w strefie jej zasilania. Drugim urządzeniem była przegroda z trzema oknami przelewowymi. Głównym celem użycia tych urządzeń było umieszczenie przeszkód na drodze przepływu stali wymuszających spokojne mieszanie cieczy metalicznej jak również ukierunkowanie płynięcia metalu w górę umożliwiające flotacyjne unoszenie wtrąceń do warstwy żużla. Wizualizacje oddziaływania zabudowy kadzi pośredniej na warunki hydrodynamiczne uzyskano na podstawie wyników otrzymanych z symulacji komputerowej przepływu ciekłej stali. W wyniku obliczeń numerycznych otrzymano pola predkości i temperatury ciekłej stali. Badano w ten sposób wpływ modyfikacji wnętrza kadzi na pola prędkości w fazie ciekłej stali, które maja istotny wpływ na jakość wlewka ciagłego odlewania.

Źródło:

Archives of Metallurgy and Materials; 2012, 57, 4; 1163-1169
1733-3490

Pojawia się w:

Archives of Metallurgy and Materials

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 38.

Tytuł:

Numerical simulations of acoustic waves with the graphic acceleration GAMER code

Autorzy:

Murawski, K.
Schive, H.

Powiązania:

https://bibliotekanauki.pl/articles/201677.pdf

Data publikacji:

2012

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

numerical simulation
acoustic waves
graphic acceleration GAMER code

Opis:

We present results of numerical simulations of acoustic waves with the use of the Graphics Processing Unit (GPU) acceleration GAMER code which implements a second-order Godunov-type numerical scheme and adaptive mesh refinement (AMR). The AMR implementation is based on constructing a hierarchy of grid patches with an octree data structure. In this code a hybrid model is adopted, in which the time-consuming solvers are dealt with GPUs and the complex AMR data structure is manipulated by Central Processing Units (CPUs). The code is highly parallelized with the Hilbert space-filling curve method. These implementations allow us to resolve well desperate spatial scales that are associated with acoustic waves. We show that a localized velocity (gas pressure) pulse that is initially launched within a uniform and still medium triggers acoustic waves simultaneously with a vortex (an entropy mode). In a flowing medium, acoustic waves experience amplitude growth or decay, a scenario which depends on a location of the flow and relative direction of wave propagation. The amplitude growth results from instabilities which are associated with negative energy waves.

Źródło:

Bulletin of the Polish Academy of Sciences. Technical Sciences; 2012, 60, 4; 787-792
0239-7528

Pojawia się w:

Bulletin of the Polish Academy of Sciences. Technical Sciences

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 39.

Tytuł:

Morphogenesis and correction of planar rod constructions with a small amount of free nodes
Formoobrazovanie i korrekcija ploskikh sterzhnevykh konstrukcijj s nebolshim kolichestvom svobodnykh uzlov

Autorzy:

Skochko, V.

Powiązania:

https://bibliotekanauki.pl/articles/77223.pdf

Data publikacji:

2015

Wydawca:

Komisja Motoryzacji i Energetyki Rolnictwa

Tematy:

morphogenesis
rod construction
frame
geometrical modelling
numerical simulation

Źródło:

Motrol. Motoryzacja i Energetyka Rolnictwa; 2015, 17, 8
1730-8658

Pojawia się w:

Motrol. Motoryzacja i Energetyka Rolnictwa

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 40.

Tytuł:

Numerical simulation of drilling fluid flow in annular the space of the borehole

Autorzy:

Kowalska-Kubsik, I.

Powiązania:

https://bibliotekanauki.pl/articles/299058.pdf

Data publikacji:

2015

Wydawca:

Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH

Tematy:

numerical simulation
fluid flow
drilling fluids
rheological models

Opis:

This paper presents the numerical results of a numerical analysis of drilling fluid flow through annular space in the borehole. The analysis used the Herschel–Bulkley rheological fluid model. The obtained results of the analysis for three cases with variable geometry. Variable geometry is associated with a larger diameter drill in the joints of drill pipes, and consequently, with reduced flow cross-section. A comparison of pressure values at the end of the analyzed examples showed that in the example of a simple drill pipe without joints, pressure values were 30% higher than in the case, which takes into account changes in the geometry of the joints.

Źródło:

AGH Drilling, Oil, Gas; 2015, 32, 4; 775-783
2299-4157
2300-7052

Pojawia się w:

AGH Drilling, Oil, Gas

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 41.

Tytuł:

FEM Simulation of Deep Drawing Process of Aluminium Alloys

Autorzy:

Slota, J.
Gajdos, I.
Jachowicz, T.
Siser, M
Krasinskyi, V.

Powiązania:

https://bibliotekanauki.pl/articles/117816.pdf

Data publikacji:

2015

Wydawca:

Polskie Towarzystwo Promocji Wiedzy

Tematy:

deep drawing
Al alloys
sheet metal
numerical simulation

Opis:

This paper presents results of research with FEM simulation of sheet metal forming process. The two types of aluminium alloys from 5XXX and 6XXX series, which are used in automotive industry, were compared. The computer simulation and numerical analysis of deep drawing cup test were used to predict the ability of the forming of these alloys. The plasticity model Hill'90 was used for stamping simulations. The results of numerical simulation were validated by real experiment using sheet metal testing machine Erichsen 145-60. Both results were compared with regard to prediction accuracy in changes of thickness and ear profile.

Źródło:

Applied Computer Science; 2015, 11, 4; 7-19
1895-3735

Pojawia się w:

Applied Computer Science

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 42.

Tytuł:

Porównanie możliwości analizy cylindrycznych elementów energochłonnych obciążonych impulsem wybuchu w systemach LS-dyna i MSD Dytran
Analysis of blast loaded energy absorbing elements using LS-dyna and MSC.Dytran systems

Autorzy:

Dacko, M.
Nowak, J.

Powiązania:

https://bibliotekanauki.pl/articles/387005.pdf

Data publikacji:

2008

Wydawca:

Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej

Tematy:

MSC Dytran
LS-DYNA
symulacja numeryczna
numerical simulation

Opis:

W pracy przedstawiono problematykę modelowania elementów cylindrycznych obciążonych falą ciśnienia powstałą w wyniku detonacji ładunku materiału wybuchowego. Symulację numeryczną przeprowadzono w środowiskach programów MSC Dytran i LS-Dyna. Utworzono model numeryczny stanowiska do badań pakietów elementów cylindrycznych składającego się z nieodkształcalnej podstawy i przymocowanej do niej płyty bazowej. Stworzono model elementu energochłonnego. Obciążenie realizowano poprzez przyłożenie zmiennego w czasie ciśnienia do pokrywy górnej cylindra. Wyniki obliczeń numerycznych porównano z wynikami otrzymanymi na drodze eksperymentalnej.
The paper presents the problems of modeling cylindrical specimens, loaded by pressure wave from the blast of explosive charge. The numerical simulation was performed using MSC.Dytran and LS-Dyna. The test rig was setup in numerical model. It consisted of rigid base and the base plate resting on it. The model of energy absorbing cylinder was created. The load was modeled by applying a varying pressure to the top cover of the cylinder. The results of numerical simulation was compared to the results of experiments

Źródło:

Acta Mechanica et Automatica; 2008, 2, 1; 13-20
1898-4088
2300-5319

Pojawia się w:

Acta Mechanica et Automatica

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 43.

Tytuł:

Protocol to define material behaviour and failure strain level at low and high strain rates based on a compression test

Autorzy:

Jankowiak, T.
Rusinek, A.
Bendarma, A.

Powiązania:

https://bibliotekanauki.pl/articles/281177.pdf

Data publikacji:

2018

Wydawca:

Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej

Tematy:

stress triaxiality
dynamic compression
material behaviour
numerical simulation

Opis:

Compression test is frequently used to define material behaviour. However, this test may be depending on different effects, for example friction, specimen inertia or local stress triaxiality. For this reason, a new design is proposed to analyse the previous effects and to try to minimize it on quantities measured as macroscopic stress and strain. To have a complete understanding, numerical simulations have been performed using finite element method (Abaqus/Standard and Abaqus/Explicit). It allows one to define the macroscopic behaviour and to have an access to the local values not accessible during experiments for a better understanding of the experimental measurements.

Źródło:

Journal of Theoretical and Applied Mechanics; 2018, 56, 2; 471-481
1429-2955

Pojawia się w:

Journal of Theoretical and Applied Mechanics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 44.

Tytuł:

Modelling of tracked vehicle dynamics

Autorzy:

Kciuk, S.
Mężyk, A.

Powiązania:

https://bibliotekanauki.pl/articles/246193.pdf

Data publikacji:

2010

Wydawca:

Instytut Techniczny Wojsk Lotniczych

Tematy:

multibody
trucked vehicle
numerical simulation
dynamical analysis
suspension

Opis:

The paper presents the problem of modelling dynamics of motor vehicles in the convention of multi-segment systems. The assumptions used in modelling process arepresented and the characteristics of elastic - damping elements of tracked vehicle suspension system are determined. This paper presents the identified mass and the geometrical parameters of the vehicle, on the basis of these parameters in Virtual.Lab software environment the simulation model was developed. The model describes the elements of a tank that does not change their position relative to the reference coordinate system, they are: the turret, muzzle, body case, and other components such as: wheels, torsion shafts, damper levers and links. The tank tracks are omitted in the simulation model. The results of numerical simulations in the form of displacement courses of characteristic points of the hull and displacements of the wheels axles in an assumed reference coordinate system are also included. The simulation results were compared with experimental results obtained on the proving ground. The results of experimental measurements carried out on the tank range, were used to precise tune a mathematical model of the vehicle. The results of numerical simulations confirmed validity ofthe assumptions in the modelling process, since good agreement was obtained with results from experimental investigations. The developed models will be used to optimize the characteristics of vehicle suspension.

Źródło:

Journal of KONES; 2010, 17, 1; 223-232
1231-4005
2354-0133

Pojawia się w:

Journal of KONES

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 45.

Tytuł:

Heeling moment acting on a river cruiser in manoeuvring motion

Autorzy:

Tabaczek, T.
Kulczyk, J.

Powiązania:

https://bibliotekanauki.pl/articles/258967.pdf

Data publikacji:

2016

Wydawca:

Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa

Tematy:

river cruiser
turning manoeuvre
heeling moment
numerical simulation

Opis:

By using fully theoretical method the heeling moment due to centrifugal forces has been determined for a small river cruiser in turning manoeuvre. The authors applied CFD software for determination of hull hydrodynamic forces, and open water characteristics of ducted propeller for estimation of thrust of rudder-propellers. Numerical integration of equations of 3DOF motion was used for prediction of ship trajectory and time histories of velocities, forces and heeling moment.

Źródło:

Polish Maritime Research; 2016, 1; 45-51
1233-2585

Pojawia się w:

Polish Maritime Research

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 46.

Tytuł:

Numerical investigation of flooding of real-topography developed areas following river embankment failure

Autorzy:

Szydłowski, M.
Twaróg, B.

Powiązania:

https://bibliotekanauki.pl/articles/1955326.pdf

Data publikacji:

2006

Wydawca:

Politechnika Gdańska

Tematy:

numerical simulation
river embankment failure
inundation
developed area

Opis:

The paper concerns numerical simulations of flood wave propagation in an urban area resulting from a river embankment failure. Simulations have been performed to predict and analyze the parameters of flash and catastrophic flow in a developed area with the aim of presenting numerical calculations useful for identification of inundation zones. The shallow water equations were assumed as the mathematical model of free-surface unsteady water flow. A numerical scheme of the finite volume method was applied to solve the model equations and the Roe method used to approximate the mass and momentum fluxes. Two test cases of embankment failure are investigated in the paper. The aim of one experiment is to simulate a flood in a model city area, where a group of buildings representing a simplified urban configuration was introduced. In order to verify the calculations, numerical results were examined against experimental data available from laboratory measurements. An experiment of the model city's flooding event was carried out at the hydraulic laboratory of the Gdansk University of Technology. The other test case concerns flash flood simulation on an embanked developed area of real topography.

Źródło:

TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2006, 10, 3; 321-338
1428-6394

Pojawia się w:

TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 47.

Tytuł:

Numerical simulation of transient flow in storm sewers using standard and improved McCormack scheme

Autorzy:

Szydłowski, M.
Machalińska-Murawska, J.

Powiązania:

https://bibliotekanauki.pl/articles/1933987.pdf

Data publikacji:

2012

Wydawca:

Politechnika Gdańska

Tematy:

mathematical modeling
numerical simulation
transient flow
storm sewers

Opis:

This paper describes the results of the first part of the research project which aims at developing a hydraulic model for simulation of unsteady flows in storm sewers ranging from gravity flows to surcharged flows resulting with water outflow on the ground surface and propagation of inundation in the flooded area. The paper focuses on the development and assessment of a second-order explicit numerical scheme for unsteady flows in sewers, but only in a single pipe at this moment, without any special elements such as manholes or drop shafts and with no water overflowing problem. The problem of water flow in sewer system pipes is associated with some specific phenomena occurring in conduits during storm events. If the pipes start to be fully filled with water, there is a transition from free surface to pressurized flow. Then, the vice versa effect can be observed. Such transitions are also possible in sewers when the discharge is controlled by control devices, such as gates for example. Moreover, the rapidly varied flow with some hydraulic local effects such as hydraulic jumps or bores can appear during extreme rain episodes. The appropriate modeling techniques have to be applied to solve these problems. The ‘Preissmann slot’ concept is implemented to simulate the pressurized flow. The original and improved McCormack scheme is used for transcritical flow simulation. The calculated results obtained for some benchmark tests are compared with numerical solutions and laboratory measurements published in the technical literature.

Źródło:

TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2012, 16, 1-2; 53-74
1428-6394

Pojawia się w:

TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 48.

Tytuł:

Numerical and Laboratory Tests of Aluminum Profile Connection Using the "Popular Lock"

Autorzy:

Golewski, P.
Sadowski, T.

Powiązania:

https://bibliotekanauki.pl/articles/356834.pdf

Data publikacji:

2019

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

bolt-channel
numerical simulation
popular lock
aluminium profile

Opis:

Aluminum profiles play an important role in civil engineering (facades, walls with windows) as well as in mechanical engineering (production lines, constructions of 3D printers and plotters). To ensure quick assembly, disassembly or changed the dimensions of constructions it is not possible to use such methods as welding, adhesive or riveting joints. The solution may be to use the so-called "popular lock”. It is a mechanism, the closure of which is caused by tightening of the conical screw, joining the "T" profile in the node. In order to properly design using the presented type of connection, it is necessary to know its strength and stiffness both in simple and complex loads states, also including imperfections. In the literature there is no information about the operation of the construction node with the so-called "popular lock”. The paper presents the results of experimental tests for connections subjected to uniaxial tensile test, paying special attention to the defects that may appear during the assembly. In the next step, a 3D solid connection model was created. Numerical simulations were performed in the Abaqus / Explicite program for both uniaxial tensile test and bending tests in two planes. Limit values of loads above which there is a plastic deformation of the material were determined. Determination of stiffness and strength of a single node allowed to make a simplified connector model. Using the numerical model, the analysis was performed taking into account the influence of imperfections on the work of the entire connection.

Źródło:

Archives of Metallurgy and Materials; 2019, 64, 1; 339-346
1733-3490

Pojawia się w:

Archives of Metallurgy and Materials

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 49.

Tytuł:

Modelling and Simulation of the Magnesium Primary Phase Crystallization in the AZ91/SiCp Composite Dependent on Mass Fraction of SiCp

Autorzy:

Lelito, J.
Krawiec, H.
Vignal, V.
Gracz, B.
Żak, P. L.
Szucki, M.

Powiązania:

https://bibliotekanauki.pl/articles/356885.pdf

Data publikacji:

2019

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

numerical simulation
AZ91/SiCp composite
micro-model

Opis:

The aim of this work is to develop a numerical model capable of predicting the grain density in the Mg-based matrix phase of an AZ91/SiC composite, as a function of the total mass fraction of the embedded SiC particles. Based on earlier work in a range of alloy systems, we assume an exponential relationship between the grain density and the maximum supercooling during solidification. Analysis of data from cast samples with different thicknesses, and mass fractions of added SiCp, permits conclusions to be drawn on the role of SiCp in increasing grain density. By fitting the data, an empirical nucleation law is derived that can be used in a micro model. Numerical simulation based on the model can predict the grain density of magnesium alloys containing SiC particles, using the mass fraction of the particles as inputs. These predictions are compared with measured data.

Źródło:

Archives of Metallurgy and Materials; 2019, 64, 1; 29-32
1733-3490

Pojawia się w:

Archives of Metallurgy and Materials

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 50.

Tytuł:

Research on forced cooling of machine tools and its operational effects

Autorzy:

Jedrzejewski, Jerzy
Winiarski, Zdzislaw
Kwasny, Wojciech

Powiązania:

https://bibliotekanauki.pl/articles/99923.pdf

Data publikacji:

2020

Wydawca:

Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych

Tematy:

machine tool
numerical simulation
forced cooling
effects
development

Opis:

The aim of this paper was to analyse in depth the existing research on the effectiveness of forced cooling and the directions in its improvement and development against the background of the increasing needs of machine tools and machining processes. The forced cooling methods used and their importance from the point of view of the development of machine tools are discussed. A detailed review of the state of the art in this field, including the latest research reports, is carried out. The essence and methods of forced cooling parameters improvement through holistic modelling, numerical simulations and optimization are presented. Moreover, the currently achievable effectiveness of forced cooling is illustrated with the results of the research conducted by the authors. Finally, conclusions are drawn and suggestions concerning the future research in this field are put forward.

Źródło:

Journal of Machine Engineering; 2020, 20, 2; 18-38
1895-7595
2391-8071

Pojawia się w:

Journal of Machine Engineering

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 51.

Tytuł:

Using the real-time simulator for prototyping power electronics inverter

Autorzy:

Baszynski, M.
Szlosek, M.

Powiązania:

https://bibliotekanauki.pl/articles/140638.pdf

Data publikacji:

2018

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

numerical simulation
rectifiers
active filters
Real time systems

Opis:

This paper deals with real-time (RT) simulators applied in power electronic applications and implemented in a real inverter. The process of preparing and starting up an active rectifier prototype (with an active filter function), using the real-time OPAL RT simulator is given. The control system of the converter and the results of simulation using the Matlab/Simulink suite are discussed.

Źródło:

Archives of Electrical Engineering; 2018, 67, 2; 447--460
1427-4221
2300-2506

Pojawia się w:

Archives of Electrical Engineering

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 52.

Tytuł:

Thermal Modelling for Production of Hot Strip of Magnesium Alloy

Autorzy:

Nam, A.
Prufert, U.
Kawalla, R.

Powiązania:

https://bibliotekanauki.pl/articles/99479.pdf

Data publikacji:

2014

Wydawca:

Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych

Tematy:

magnesium coil heating
nonlinear heat transfer
numerical simulation

Opis:

The paper deals with a thermal modelling of a magnesium coil in the magnesium strip production. The magnesium coil heating is the preparation step for the magnesium hot strip rolling and occurs in the special air circulating furnace. The cooling of the coil takes place on the several steps such as a transport of coil after heating from the furnace to a mill coiler. The aim of the work is to develop a tool to accurately simulate the temperature distribution within coil during the magnesium coil heating in the furnace. The major thermal properties for material and furnace were determined indirectly based on experimental data. Simulation results are compared to data obtained from experimental trials.

Źródło:

Journal of Machine Engineering; 2014, 14, 1; 29-38
1895-7595
2391-8071

Pojawia się w:

Journal of Machine Engineering

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 53.

Tytuł:

Numerical simulations of blast loads from near-field ground explosions in ai

Autorzy:

Dobrociński, S.
Flis, L.

Powiązania:

https://bibliotekanauki.pl/articles/178782.pdf

Data publikacji:

2015

Wydawca:

Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej

Tematy:

near-field
blast load
numerical simulation
high explosive

Opis:

Numerical simulations of air blast loading in the near-field acting on the ground have been performed. A simplified blast model based on empirical blast loading data representing spherical and hemispherical explosive shapes has been simulated. Conwep is an implementation of the empirical blast models presented by Kingery and Bulmash, which is also implemented in the commercial code LS-DYNA based on work done by Rahnders-Pehrson and Bannister. This makes it possible to simulate blast loads acting on structures representing spherical and hemispherical explosive shapes of TNT with reasonable computational effort as an alternative to the SPH and Eulerian model. The CPU time for the simplified blast model is however considerably shorter and may still be useful in time consuming concept studies. Reasonable numerical results using reasonable model sizes can be achieved not only for modelling near-field explosions in air but most areas of geotechnical. Calculation was compared with blast SPH and Eulerian model.

Źródło:

Studia Geotechnica et Mechanica; 2015, 37, 4; 11-17
0137-6365
2083-831X

Pojawia się w:

Studia Geotechnica et Mechanica

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 54.

Tytuł:

Numerical simulations by Godunov-type schemes of air-pollutant dynamics

Autorzy:

Murawski, K.
Michalczyk, J. K.

Powiązania:

https://bibliotekanauki.pl/articles/1955805.pdf

Data publikacji:

2001

Wydawca:

Politechnika Gdańska

Tematy:

numerical simulation
numerical discretization
hydrodynamic equations
distrubution of air-pollutants

Opis:

In this paper several aspects associated with numerical simulations of hyperbolic equations are discussed. This presentation covers a range of modern shock-capturing schemes which are based on Godunov-type techniques. These schemes are well suited for strong shocks and other discontinuities, without generating spurious oscillations in the flow variables. An example of a performance of such schemes is provided to simulate the spatial distribution of air-pollutants which are emitted from a chimney. The simulations are performed in the framework of two-dimensional hydrodynamics, with a use of the CLAWPACK code (R.J.LeVeque, CLAWPACK User Notes, Applied Mathematics,Univ. of Washington, Seattle, 1997a). The model reproduces several features of the distribution, including occurrence of vortices and plumes above the chimney.

Źródło:

TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2001, 5, 2; 207-228
1428-6394

Pojawia się w:

TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

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Skocz do pozycji: 55.

Tytuł:

Numerical simulation of spontaneously condensing flows in a plane turbine cascade

Autorzy:

Li, L.
Li, G.
Feng, Z.

Powiązania:

https://bibliotekanauki.pl/articles/1986685.pdf

Data publikacji:

2002

Wydawca:

Politechnika Gdańska

Tematy:

wet steam
condensing flow
Eulerian/Eulerian model
numerical simulation

Opis:

The low efficiency of wet steam turbine is mainly attributed to wetness losses. To investigate the mechanisms which give rise to these losses, a fully Eulerian model has been developed for calculation of the wet steam flows with spontaneous condensation. In this model, the liquid phase is described with two conservation equations in Eulerian form and coupled with a solver of gas dynamics equations. With such a model, the existing code for simulation of single-phase flows can easily be changed to include wet steam two-phase flows in wet steam turbines. A numerical simulation of condensing flow in a plane turbine cascade is performed, and the numerical results are presented and compared with the experimental results.

Źródło:

TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2002, 6, 1; 209-216
1428-6394

Pojawia się w:

TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

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Skocz do pozycji: 56.

Tytuł:

Application of variational and fem methods to the modelling and numerical analysis of the slitting process for geometrical and physical nonlinearity

Autorzy:

Bohdal, Ł.
Kukiełka, L.

Powiązania:

https://bibliotekanauki.pl/articles/279477.pdf

Data publikacji:

2015

Wydawca:

Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej

Tematy:

slitting
constitutive laws
modelling
numerical simulation
variational formulation
FEM

Opis:

Finite element modelling provides a great deal of support in the understanding of technological processes. However, there are few studies of the slitting process, and those that exist are simplified for use only in the calculation of steady states of such processes. This paper proposes the application of variational and finite element methods for the analysis of slitting and the nonlinearities of this process. Physical and mathematical models of the process and a new thermo-elastic/thermo-visco-plastic material model are elaborated. The procedure is implemented in the finite element code ANSYS/LS-DYNA and the model is validated comparing the numerical and experimental results. The influence of various process conditions on the strain and stress states and the quality of the final product are analysed. The results lay the groundwork for further study regarding the numerical analysis of spring-back behaviour and the effect of tool elasticity on the quality of the final workpiece.

Źródło:

Journal of Theoretical and Applied Mechanics; 2015, 53, 2; 487-500
1429-2955

Pojawia się w:

Journal of Theoretical and Applied Mechanics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 57.

Tytuł:

Numerical study of droplet formation in a Y-junction microchannel

Autorzy:

Diouf, M. M. L.
Romero, O. J.

Powiązania:

https://bibliotekanauki.pl/articles/281676.pdf

Data publikacji:

2017

Wydawca:

Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej

Tematy:

microfluidic
Y-junction
two-phase flow
numerical simulation
VOF

Opis:

This study investigates the formation process of droplets in a Y-junction microchannel using two immiscible fluids: water as the continuous fluid and oil as the dispersed phase. We have examined the influence of the capillary number, flow rate ratio and viscosity ratio between the two fluids; parameters which determine the length and generation frequency of the droplets. Numerical simulations have been performed using the software Ansys Fluent with the interface capture method Volume of Fluid (VOF) for solving the governing equations. Three different algorithms have been tested for the pressure-velocity coupling: SIMPLE, SIMPLEC and PISO. The results are quite similar for SIMPLE and SIMPLEC, however it turned out that PISO is a better algorithm to solve the two-phase flow. Additionally, another Y-junction is coupled in the initial geometry to observe a symmetric breakup of the droplets and their formation is explained using the pressure field and the velocity field.

Źródło:

Journal of Theoretical and Applied Mechanics; 2017, 55, 1; 317-330
1429-2955

Pojawia się w:

Journal of Theoretical and Applied Mechanics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 58.

Tytuł:

Investigation of the cook-off processes of HMX-based mixed explosives

Autorzy:

Chen, L.
Ma, X.
Lu, F.
Wu, J.

Powiązania:

https://bibliotekanauki.pl/articles/358000.pdf

Data publikacji:

2014

Wydawca:

Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego

Tematy:

explosives
chemical kinetics
thermal decomposition
cook-off
numerical simulation

Opis:

In order to investigate the characteristics of the thermal reaction for two kinds of mixed explosives, PBXC-10 (HMX/TATB/Binder, 38/57/5) and JO-8 (HMX/Binder, 95/5), multi-point measured temperature cook-off tests were carried out at different heating rates. The thermal transfer and finite chemical reactions that include the β→δ transition of HMX, and the endothermic and exothermic cook-off processes were analyzed. A 3D model of the explosive cook-off test was developed to simulate the thermal and chemical behaviour in a thermal ignition. The decomposition mechanisms for HMX and TATB are described by the multistep, chemical kinetic model. The thermal properties, decomposition pathways, and chemical kinetic reaction rate constants for each component are used to develop the reaction courses at various weight percentages. The thermal decomposition reaction of a multi-component, mixed explosive can be predicted as long as the chemical kinetics model of each single-base explosive and binder are known. The phase transition of HMX has an influence on the temperature of the explosive, especially for an explosive with a high HMX content. For mixed explosives containing HMX and TATB, most of the heat release is produced by the decomposition of HMX before ignition, but TATB can delay the ignition time and decrease the reaction violence in the cook-off process.

Źródło:

Central European Journal of Energetic Materials; 2014, 11, 2; 199-218
1733-7178

Pojawia się w:

Central European Journal of Energetic Materials

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 59.

Tytuł:

Study on the Initiation Capacities of Conical Ring Booster Pellets

Autorzy:

Hu, L.
Hu, S.
Cao, X.
Li, J.

Powiązania:

https://bibliotekanauki.pl/articles/358594.pdf

Data publikacji:

2014

Wydawca:

Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego

Tematy:

booster pellet
main charge
initiation capacity
numerical simulation
optimization

Opis:

The insensitive main charge explosive is becoming an important part of modern weapon development. Insensitive main charge explosives generally have a high critical initiation pressure. The detonation pressure of a traditional cylindrical booster pellet is constant at a specific density and consequently has insufficient energy output to reliably initiate an insensitive main charge explosive. To ensure that this requirement could be achieved, the conical ring booster pellet was designed and optimized. Eight-point-synchronous explosive circuits were designed as appropriate to the sizes of the four booster pellets. The initiation processes of the four conical booster pellets equipped with the eight-point circuit were simulated using ANSYS/LY-DYNA software. The experimental measurements were performed in order to test the initiation capacities of these conical booster pellets. The results demonstrated that their initiation capacities are much better than the initiation capacity of a cylindrical booster pellet. The optimum size of the conical ring booster pellet is when the ratio of the inner to the upper diameter is 0.52, the ratio of the inner to the lower diameter is 0.44, and the ratio of the height to the lower diameter is 0.50.

Źródło:

Central European Journal of Energetic Materials; 2014, 11, 3; 335-348
1733-7178

Pojawia się w:

Central European Journal of Energetic Materials

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 60.

Tytuł:

Drag force on a flat plate in cavitating flows

Autorzy:

Seif, M. S.
Asnaghi, A.
Jahanbakhsh, E.

Powiązania:

https://bibliotekanauki.pl/articles/258824.pdf

Data publikacji:

2009

Wydawca:

Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa

Tematy:

numerical simulation
cavitation
psio algorithm
flat plate
unsteady flow

Opis:

The present study focuses on the simulation of two dimensional unsteady cavitating flows. For simulation of unsteady behaviors of cavitation which have practical applications, the development of unsteady PISO algorithm based on the non-conservative approach is utilized. For multi-phase simulation, single-fluid Navier–Stokes equations, along with the volume fraction transport equation, are employed. The bubble dynamics model is utilized to simulate phase change between vapor and liquid phases of the water. Unsteady simulation of cavitation around NACA66(MOD) and supercavitation around a flat plate normal to flow direction are performed to clarify accuracy of presented model. Numerical results and comparisons with experimental data are provided. The accuracy is good, and it is possible to apply this method to more complex shapes.

Źródło:

Polish Maritime Research; 2009, 3; 18-25
1233-2585

Pojawia się w:

Polish Maritime Research

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 61.

Tytuł:

Study on striking ship with loading impact on the performance of the double hull oil tanker collision

Autorzy:

Wu, W.
Yang, Y.
Zhang, J.
Lu, J.

Powiązania:

https://bibliotekanauki.pl/articles/258890.pdf

Data publikacji:

2018

Wydawca:

Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa

Tematy:

ship collision
fluid-structure interaction
impact parameters
numerical simulation

Opis:

Due to the great danger of the collision of oil tankers, lots of research on the collision of oil tankers has been carried out. But, at present, the research on the collision of oil tankers mainly focuses on the loading condition of the struck ship, ignores the impact on the loading condition of the striking ship. However, during the actual oil tanker collision, the striking ship is generally in the state of loading. Therefore, it is necessary to carry out the analysis of the impact of the loading condition of the striking ship on the collision damage of the oil tanker. In this paper, the effect of striking ship with loading on the impact performance of the side structure during the collision of the cargo double hull oil tanker has been investigated. The ship collision model was established by using the finite element software ANSYS/ LS-DYNA which is based on 7000 tons of double hull oil tankers. Based on the analysis of the collision force, impact of striking speed changes, impact of striking deep changes and structural energy absorption during the collision process, the influence of the striking ship with loading on the damage mechanism and the impact performance of the double shell oil ship side structure was expounded. The results show that the influence of the striking ship with loading can be great to the damage to side hull during the research of the collision performance of the oil tanker.

Źródło:

Polish Maritime Research; 2018, S 2; 42-48
1233-2585

Pojawia się w:

Polish Maritime Research

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 62.

Tytuł:

Numerical simulation study on exposed reinforced anti-corrosion layer damage of the cross-sea bridge under the marine environment

Autorzy:

Qu, H.
Su, J.
Huang, P.
Ren, X.

Powiązania:

https://bibliotekanauki.pl/articles/259261.pdf

Data publikacji:

2017

Wydawca:

Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa

Tematy:

cross-sea bridge
reinforced
anti-corrosion damage
numerical simulation

Opis:

To solve the problem of low precision of numerical simulation of the exposed reinforced anti-corrosion layer damage of the cross-sea bridge, we use the stress ratio between the double slash and the reinforced anti-corrosion layer to analyze the parameters and the damage rate in different qualities of reinforced anti-corrosion layers, use Ansys software to build reinforced finite element model, and analyze the damage degree when the inclination angle was 15 °, 45 ° and 60 °, respectively. The experimental results showed that the proposed method can improve the numerical simulation efficiency, the numerical simulation results, the experimental results, and the theoretical analysis results have good consistency and stability.

Źródło:

Polish Maritime Research; 2017, S 3; 207-212
1233-2585

Pojawia się w:

Polish Maritime Research

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 63.

Tytuł:

Lax-Wendroff and McCormack Schemes for Numerical Simulation of Unsteady Gradually and Rapidly Varied Open Channel Flow

Autorzy:

Machalińska-Murawska, J.
Szydłowski, M.

Powiązania:

https://bibliotekanauki.pl/articles/973864.pdf

Data publikacji:

2013

Wydawca:

Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN

Tematy:

open channel flow
mathematical modeling
numerical simulation
FDM schemes

Opis:

Two explicit schemes of the finite difference method are presented and analyzed in the paper. The applicability of the Lax-Wendroff and McCormack schemes for modeling unsteady rapidly and gradually varied open channel flow is investigated. For simulation of the transcritical flow the original and improved McCormack scheme is used. The schemes are used for numerical solution of one dimensional Saint-Venant equations describing free surface water flow. Two numerical simulations of flow with different hydraulic characteristics were performed – the first one for the extreme flow of the dam-break type and the second one for the simplified flood wave propagation problem. The computational results are compared to each other and to arbitrary solutions.

Źródło:

Archives of Hydro-Engineering and Environmental Mechanics; 2013, 60, 1-4; 51-62
1231-3726

Pojawia się w:

Archives of Hydro-Engineering and Environmental Mechanics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 64.

Tytuł:

Numerical investigation of heat exchange in rotary furnace

Autorzy:

Kolczyk, E.
Miczkowski, Z.
Czernecki, J.

Powiązania:

https://bibliotekanauki.pl/articles/354348.pdf

Data publikacji:

2017

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

numerical simulation
heat exchange
rotary furnace
slag reduction process

Opis:

Process of heat exchange in a rotary furnace during converter slag reduction was modelled.Temperature distribution in the furnace and temperature of the charge (slag) only were examined. Influence of modification of the process gas supply method by changing the number of nozzles on the course of the reduction process was analyzed. It has been found out that application of a nozzle as a submerged flame burner provides possibilities to reach higher charge temperature. Application of more nozzles in the process of converter slag reduction can increase temperature of reduced slag and provide better uniformity of charge heating.

Źródło:

Archives of Metallurgy and Materials; 2017, 62, 1; 149-153
1733-3490

Pojawia się w:

Archives of Metallurgy and Materials

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 65.

Tytuł:

Fatigue Life Predicting for Nitrided Steel - Finite Element Analysis

Autorzy:

Sawicki, J.
Siedlaczek, P.
Staszczyk, A.

Powiązania:

https://bibliotekanauki.pl/articles/355788.pdf

Data publikacji:

2018

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

numerical simulation
nitriding
fatigue life
fatigue analysis
finite element

Opis:

Thermo-chemical treatments are known to increase the fatigue life of industrial parts. Due to the imprecise consideration of residual stresses in predicting the durability of components subjected to cyclic loading and their effect on the fatigue life, the authors developed a numerical model combining the influence of residual stresses with stresses caused by bending. The authors performed the numerical simulation with the use of Finite Element Method to analyse material behaviour during cyclic loading. The residual stress state developed during nitriding was introduced onto cross-section of the numerical specimen. The goal of this work was better understanding of the real conditions of the nitride steel fatigue processes and improving the knowledge about numerical predicting of the fatigue life for parts with residual stresses. The results of simulation were compared with plane bending fatigue tests. The presented method indicates the possibility of increasing the accuracy of the fatigue analysis of elements after surface treatment, increasing its certainty and the ability to perform better optimization of service life.

Źródło:

Archives of Metallurgy and Materials; 2018, 63, 2; 921-927
1733-3490

Pojawia się w:

Archives of Metallurgy and Materials

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 66.

Tytuł:

Analysis of forming thin titanium panels with stiffeners

Autorzy:

Adamus, J.
Winowiecka, J.
Dyner, M.

Powiązania:

https://bibliotekanauki.pl/articles/352785.pdf

Data publikacji:

2017

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

commercially pure titanium
sheet
numerical simulation
sheet metal forming

Opis:

The growing demand for light and durable products has caused an increase in interest in products formed of thin sheets. In order to ensure sufficient stiffness of the drawn - parts, stiffening is often performed. Unfortunately, during the forming of stiffeners unwanted deformations of the drawn parts very often appear, which prevent them from further exploitation. In the paper, forming thin titanium panels with stiffeners is analysed. The panels are made of sheets of commercially pure titanium: Grades 2, 3 and 4. In the results of numerical analyses which were performed using PamStamp 2G, taking into consideration the impact of the blank holder force and friction conditions on the strain distribution in the drawn parts, sheet thinning and springback values are presented. The numerical analysis results were compared with the experimental tests. It was concluded that in order to prevent panel deformation being a result of residual stresses, it is necessary to ensure adequate friction conditions on the contact surfaces between the deformed material and tools as well as a suitable blank holder force.

Źródło:

Archives of Metallurgy and Materials; 2017, 62, 1; 173-180
1733-3490

Pojawia się w:

Archives of Metallurgy and Materials

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 67.

Tytuł:

Badanie efektu dylatancji w numerycznym modelu próbki skalnej
Study on the phenomenon of dilatancy of numerical models of rock samples

Autorzy:

Jendryś, M.
Kleta, H.

Powiązania:

https://bibliotekanauki.pl/articles/113071.pdf

Data publikacji:

2017

Wydawca:

STE GROUP

Tematy:

górotwór
badania numeryczne
dylatancja
rock mass
numerical simulation
dilatancy

Opis:

W artykule przedstawiono badania mające na celu określenie przebiegu procesów dylatacyjnych w podczas prób jednoosiowego i trójkierunkowego ściskania próbek walcowych z materiału ziarnistego. Symulacje przeprowadzone zostały za pomocą programów PFC2D i PFC3D pozwalających na budowę modeli z wykorzystaniem na metody elementów odrębnych. W celu opisania procesów dylatacyjnych obliczone zostały charakterystyki naprężeniowoodkształceniowe pozwalające na wyznaczenie parametrów opisujących przebieg procesów dylatacyjnych.
The paper presents results of research to determine the dilatancy in the triaxial and uniaxial compression of cylindrical samples of granular material. Simulations were carried out using the PFC2D and PFC3D programs which allow to build numerical models based on discrete elements method. To describe the effect of dilatancy the stress-strain curves were generated. On the basis of course of those curves parameters describing dilatant behavior of rock samples were assigned.

Źródło:

Systemy Wspomagania w Inżynierii Produkcji; 2017, 6, 3; 68-78
2391-9361

Pojawia się w:

Systemy Wspomagania w Inżynierii Produkcji

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 68.

Tytuł:

Mathematical modeling of large floating roof reservoir temperature arena

Autorzy:

Liu, Y.
Fan, J.
Cheng, Q.

Powiązania:

https://bibliotekanauki.pl/articles/778000.pdf

Data publikacji:

2018

Wydawca:

Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie

Tematy:

floating roof tank
temperature field
natural convection
numerical simulation

Opis:

The current study is a simplification of related components of large floating roof tank and modeling for three dimensional temperature field of large floating roof tank. The heat transfer involves its transfer between the hot fluid in the oil tank, between the hot fluid and the tank wall and between the tank wall and the external environment. The mathematical model of heat transfer and flow of oil in the tank simulates the temperature field of oil in tank. Oil temperature field of large floating roof tank is obtained by numerical simulation, map the curve of central temperature dynamics with time and analyze axial and radial temperature of storage tank. It determines the distribution of low temperature storage tank location based on the thickness of the reservoir temperature. Finally, it compared the calculated results and the field test data; eventually validated the calculated results based on the experimental results.

Źródło:

Polish Journal of Chemical Technology; 2018, 20, 1; 67-74
1509-8117
1899-4741

Pojawia się w:

Polish Journal of Chemical Technology

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 69.

Tytuł:

Experimental study and numerical simulation on fly ash separation with different plate voltages in rotary triboelectrostatic separator

Autorzy:

Zhang, L.
Tao, Y.
Tao, D.
Zhang, W.
Yang, L.

Powiązania:

https://bibliotekanauki.pl/articles/110712.pdf

Data publikacji:

2018

Wydawca:

Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej

Tematy:

fly ash
rotary triboelectrostatic separator
plate voltage
numerical simulation

Opis:

As the main solid wastes of coal-fired power plants, fly ash particles with different electrical properties are usually recycled using triboelectrostatic separator. The purpose of this study was to investigate the effect of different plate voltages on the separation of fly ash in a rotary triboelectrostatic separator with experiments and numerical simulation. The maximum values of yield of ash products (48.30%), and decarbonisation rate (50.89%) and the minimum loss-on-ignition (6.61%) were obtained when the plate voltage was 24 kV in the separation experiments, while 55.98%, 59.46%, 5.80% were reached respectively when the plate voltage was 26 kV in the simulation. In general, experimental data were similar with numerical simulation. The turning points appeared around 25 kV due to the increasing mismatch in products, which resulted from the reinforced rebound phenomena, namely the charged particle rebound from the electrode plate with a larger reflection velocity, when the plate voltage increased from 18 to 28 kV. It was validated by the numerical simulation results.

Źródło:

Physicochemical Problems of Mineral Processing; 2018, 54, 3; 722-731
1643-1049
2084-4735

Pojawia się w:

Physicochemical Problems of Mineral Processing

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 70.

Tytuł:

Dynamic analysis of a dashpots equipped vibrating screen using finite element method

Autorzy:

Khoshdast, Hamid
Jalilifard, Saeid
Khoshdast, Hami

Powiązania:

https://bibliotekanauki.pl/articles/1448575.pdf

Data publikacji:

2021

Wydawca:

Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej

Tematy:

vibrating screen
dashpots
dynamic characteristic
numerical simulation
FEM modeling

Opis:

Even though vibrating screens have been used in mining industries for over a century, their use has often been cited as challenging in terms of understanding its dynamic responses to different operating factors, particularly those that affect the structural aspects. Among the various aspects of screen design, the control of vibrational energies imposed on various parts of the screen is of particular importance because these vibrations directly affect the separation efficiency and useful life of the screen. This study proposes the use of vibration absorbers to control the adverse effects of severe screen vibrations. The dynamic behavior of a medium-sized vibrating screen utilized in the aggregate industry was investigated using the finite element method for both spring/dashpots and conventional solely spring systems. The modeling process was performed in loaded and unloaded conditions and in three frequencies of 15, 23, and 27 rad/s. Numerical simulation results showed that the use of dashpots can significantly reduce the maximum stress in the screen, such that the maximum stress in the center of gravity of the screen at the optimal frequency of 23 decreased from 237 to about 97 MPa. Also, sieve modal analysis showed that the stress in the sieve equipped with the spring/dashpots system had a more uniform distribution. The results revealed that the use of vibration absorbers can be a promising solution to prevent damage caused by high vibrational energies in screens.

Źródło:

Physicochemical Problems of Mineral Processing; 2021, 57, 1; 112-126
1643-1049
2084-4735

Pojawia się w:

Physicochemical Problems of Mineral Processing

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 71.

Tytuł:

Wstępna analiza zjawiska rykoszetowania wydłużonych penetratorów pocisków kinetycznych
Initial identification of the elongated penetrators ricochets

Autorzy:

Magier, M.

Powiązania:

https://bibliotekanauki.pl/articles/234510.pdf

Data publikacji:

2010

Wydawca:

Wojskowy Instytut Techniczny Uzbrojenia

Tematy:

pociski podkalibrowe
symulacje numeryczne
sub calibre missiles
numerical simulation

Opis:

W pracy, na podstawie krytycznej analizy literatury problemu, przedstawiono wstępną charakterystykę zjawiska rykoszetowania i niszczenia wydłużonych pocisków podkalibrowych na pochylonych pancerzach. Określono wpływ kąta podejścia pocisku do płyty oraz konstrukcji pancerza na proces penetracji pociskiem podkalibrowym.
In this paper the problem of the elongated penetrators ricochets during penetration of the oblique plates are presented. Conclusions about the influence of the pitch angle and armour profile to penetration process were formulated basing on the critical review of the literature.

Źródło:

Problemy Techniki Uzbrojenia; 2010, R. 39, z. 115; 7-17
1230-3801

Pojawia się w:

Problemy Techniki Uzbrojenia

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 72.

Tytuł:

Effect of circumferential grooves casing treatment on tip leakage flow and loss in a transonic mixed-flow compressor

Autorzy:

Qiang, X. Q.
Zhu, M. M.
Teng, J. F.

Powiązania:

https://bibliotekanauki.pl/articles/279263.pdf

Data publikacji:

2013

Wydawca:

Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej

Tematy:

compressor
casing treatment
tip leakage
flow loss
numerical simulation

Opis:

A numerical simulation of a single stage transonic mixed-flow compressor is presented. The simulation is run with a multi-passage grid that models the 3D, viscous, steady and unsteady flow field. The effect of circumferential grooves casing treatment on the compressor overall performance, tip leakage flow and loss has been studied. The results show that the narrow operating range has been significantly broaden by the casing treatment grooves, while the mismatching between the rotor and stator still exists and becomes even worse. Detailed analysis indicates that the fluid from circumferential grooves is injected into the blade passage near the suction surface and re-energizes the leakage flow, which makes mainly contribution to manipulation of the tip leakage flow and stall margin improvement. Since the pressure difference across the blade tip section has a great impact on the effectiveness of circumferential grooves, the positions of shock wave and tip leakage flow as well as where the interaction takes place ought to be taken into account through the casing treatment design procedure.

Źródło:

Journal of Theoretical and Applied Mechanics; 2013, 51, 4; 903-913
1429-2955

Pojawia się w:

Journal of Theoretical and Applied Mechanics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 73.

Tytuł:

Electromagnetically excited audible noise - evaluation and optimisation of electrical machines by numerical simulation

Autorzy:

Schlensok, C.
Schmülling, B.
Giet, M.
Hameyer, K.

Powiązania:

https://bibliotekanauki.pl/articles/262795.pdf

Data publikacji:

2006

Wydawca:

Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie

Tematy:

numerical simulation
electrical machines
FEM
BEM
acoustics
structured analysis

Opis:

Disturbing vibrations and noise of electrical machines are gaining impact. Therefore, it is necessary to estimate the electromagnetic, structure-dynamical, and acoustic behavior of the machine during designing and before prototyping. An adequate tool is numerical simulation applying the Finite-Element Method (FEM) and the Boundary-Element Method (BEM) allowing for the structured analysis and evaluation of audible noise also caused by manufacturing tolerances. The methods developed and proved at the Institute of Electrical Machines (IEM) at RWTH Aachen University can be applied to any electromagnetic device in general.

Źródło:

Electrical Power Quality and Utilisation. Journal; 2006, 12, 2; 121-128
1896-4672

Pojawia się w:

Electrical Power Quality and Utilisation. Journal

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 74.

Tytuł:

Influence of number of step reactions on flame parameters under quenching conditions

Autorzy:

Gutkowski, A.

Powiązania:

https://bibliotekanauki.pl/articles/242109.pdf

Data publikacji:

2011

Wydawca:

Instytut Techniczny Wojsk Lotniczych

Tematy:

flame propagation
quenching diameter
flame propagation velocity
numerical simulation

Opis:

Last decade, construction and using of microscale gas-turbines and internal combustion engines is collecting growing attention. However, the flame propagation limitations impede the development of micro and mesoscale combustion devices. Due to its small scale, increasing effect of flame-wall interaction causes a large heat loss and in consequence flame quenching. Both, fundamental experimental work and numerical simulations are conducted in order to overcome quenching issues. The most basic analysis concerns flame behaviour in small scale devices are premixed flame propagation in narrow tubes. There are two possibilities of flame-flow configurations: flame moving in a stationary mixture and a stationary flame in mowing mixture. These configurations have influence on flame shape, flame propagation velocity and quenching diameter. Most of numerical investigation assumes single-step reaction. It means that for flames propagating in propane-air mixtures C3H8 reacts directly with oxygen and leads to CO2 and H2O. This chemical kinetics mechanism omits existence of CO in reaction zone and in combustion products. Therefore it is interesting to use two-step reactions mechanism and compare the results with those obtained from single-step reaction model. The purpose of this analysis is to find influence of number of reaction steps on flame behaviour under quenching conditions for flames propagating in stationary lean propane-air mixtures. Quenching diameter, flame propagation velocity are determined and analyzed.

Źródło:

Journal of KONES; 2011, 18, 2; 153-159
1231-4005
2354-0133

Pojawia się w:

Journal of KONES

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 75.

Tytuł:

Experimental and numerical three-point bending test for sandwich beams

Autorzy:

Czechowski, L.
Jankowski, J.
Kotełko, M.

Powiązania:

https://bibliotekanauki.pl/articles/242768.pdf

Data publikacji:

2017

Wydawca:

Instytut Techniczny Wojsk Lotniczych

Tematy:

numerical simulation
bending tests
composite materials
sandwich beams
honeycomb

Opis:

The article deals with an experimental investigation of mechanical properties of sandwich beams obtained from bending tests. The tested specimens consisted of foam or honeycomb core and face sheets made of aluminium alloys, plywood or composite material. The face sheets and the core were bonded with glue material. Beams of different dimensions, namely beam width, as well as core and face sheets thickness, were tested. Three point bending tests were carried out, which mid span deflections of the beam versus applied force were recorded. Experimental test results were compared with simulations on the basis of finite element method. The full, non-linear analysis, taking into account large displacements and using contact elements was performed. The obtained results are presented in loaddeflection diagrams. Some conclusions concerning ultimate loads and failure behaviour of tested beams made of different materials have been derived.

Źródło:

Journal of KONES; 2017, 24, 3; 53-62
1231-4005
2354-0133

Pojawia się w:

Journal of KONES

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 76.

Tytuł:

Numerical calculations of behaviour of ship double-bottom structure during grounding

Autorzy:

Niklas, K.

Powiązania:

https://bibliotekanauki.pl/articles/963390.pdf

Data publikacji:

2008

Wydawca:

Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa

Tematy:

numerical simulation
grounding
collision
CORET project
LS-DYNA software

Opis:

The idea of the CORET project consists in adding, to the existing construction, special polymer-concrete coatings intended for the increasing of ship’s capability against losing structural tightness during collision or grounding. In order to correctly design the protective barriers, to perform relevant numerical simulations is necessary. The elaborating of numerical models of ship structure behaviour during collision is very complicated and requires auxiliary simulations (on submodels) to be performed. This paper is devoted to elaborating a numerical model of a fragment of ship double-bottom structure. On the basis of experimental tests it was possible to verify and calibrate the numerical model which may be used in further design work aimed at the increasing of crashworthiness of structure during collision.

Źródło:

Polish Maritime Research; 2008, S 1; 22-26
1233-2585

Pojawia się w:

Polish Maritime Research

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 77.

Tytuł:

Numerical study on the optimization of hydrodynamic performance of oscillating buoy wave energy converter

Autorzy:

Lai, Wenbin
Xie, Yonghe
Li, Detang

Powiązania:

https://bibliotekanauki.pl/articles/1573638.pdf

Data publikacji:

2021

Wydawca:

Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa

Tematy:

wave energy converter
hydrodynamic performance
numerical simulation
physical experiment

Opis:

The oscillating buoy wave energy converter (OBWEC) captures wave energy through the undulating movement of the buoy in the waves. In the process of capturing wave energy, the hydrodynamic performance of the buoy plays an important role. This paper designed the “Haida No. 1” OBWEC, in which the buoy adopts a form of swinging motion. In order to further improve the hydrodynamic performance of the buoy, a 2D numerical wave tank (NWT) model is established using ADINA software based on the working principle of the device. According to the motion equation of the buoy in the waves, the influence of the buoy shape, arm length, tilt angle, buoy draft, buoy width, wave height and Power Take-off (PTO) damping on the hydrodynamic performance of the buoy is studied. Finally, a series of physical experiments are performed on the device in a laboratory pool. The experimental results verify the consistency of the numerical results. The research results indicate that the energy conversion efficiency of the device can be improved by optimizing the hydrodynamic performance of the buoy. However, the absorption efficiency of a single buoy for wave energy is limited, so it is very difficult to achieve full absorption of wave energy.

Źródło:

Polish Maritime Research; 2021, 1; 48-58
1233-2585

Pojawia się w:

Polish Maritime Research

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 78.

Tytuł:

Numerical analysis of the tip vortex in an air-conditioners propeller fan

Autorzy:

Wang, J.
Wu, K.

Powiązania:

https://bibliotekanauki.pl/articles/1955218.pdf

Data publikacji:

2006

Wydawca:

Politechnika Gdańska

Tematy:

tip vortex
internal flow field
propeller fan
numerical simulation

Opis:

A steady, incompressible, turbulent flow field inside a propeller fan used in an air conditioner has been analyzed numerically using the single-equation Spalart-Allmaras turbulence model. It has been found that the formation of tip vortex starts from the blade tip's suction side at about one third of the axial chord's length aft of the rotor's leading edge. It is due to the rolling-up of the intense shear layer flow between the main axial flow and the suck-in inward flow caused by the large pressure difference between the pressure and the suction sides. The tip vortex passes through the blade passage in a curve reversed towards the direction of the blade's rotation. Its trace is partial to the tangential direction as it goes into the aft part of the blade passage covered by the shroud and, simultaneously, its trace in the radial direction is turned from the outward direction to the inward direction. The operating flow rates have an important effect on the axial position of the tip vor-tex's trace, while its effect on the radial position is negligible. At law flow rates, the vortex disappears at a location closer to the leading edge. The effect of the shroud's width on the tip vortex's trajectory is notable. For a fan with a wide shroud, the trace of the tip vortex moves upstream with a smaller radial influence region than that of a fan with a narrower shroud.

Źródło:

TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2006, 10, 2; 101-112
1428-6394

Pojawia się w:

TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 79.

Tytuł:

Numerical simulation of open channel flow between bridge piers

Autorzy:

Szydłowski, M.

Powiązania:

https://bibliotekanauki.pl/articles/1934025.pdf

Data publikacji:

2011

Wydawca:

Politechnika Gdańska

Tematy:

numerical simulation
open channel flow
mathematical modeling
bridge piers

Opis:

Free-surface flow in the vicinity of bridge piers on a fixed channel bed is a classical problem of open-channel hydraulics. This problem is usually analyzed using one-dimensional hydraulic models for steady-flow problems. The aim of this paper is to present a two-dimensional numerical simulation of water flow around obstacles, such as cylinders, which can act as a simplified model of real piers. The depth-averaged Navier-Stokes equations describing unsteady free-surface flow are solved using an explicit scheme of the finite-volume method. The numerical solution prepared for the simulations of unsteady free-surface flows was used here to analyze the case of steady flow. A numerical simulation of flow in the channel with the obstruction was performed for two different inflow discharges determining, respectively, the subcritical and supercritical flow in the cross-section of a channel constriction. In the second simulation, a hydraulic jump was observed downstream of the bridge section. The numerical results were compared with measurements. Water surface profiles were measured for both discharges in the hydraulic laboratory of the Faculty of Civil and Environmental Engineering at Gdansk University of Technology (GUT). Comparisons with laboratory data showed that the proposed approach constitutes a sufficiently accurate and reliable technique for predicting basic flow parameters. The method of two-dimensional modeling of flow in a river channel between bridge piers can be also integrated with the simulation of unsteady flood wave propagation, ensuring a uniform approach to the problem of flood modeling in river valleys. Moreover, a two-dimensional simulation yields detailed information about flow structure near the obstruction, which can be used to better elucidate debris transport and river bed deformation processes.

Źródło:

TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2011, 15, 3-4; 271-282
1428-6394

Pojawia się w:

TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 80.

Tytuł:

Comparison of safety levels required by adequate regulations for cargo ships of different types

Autorzy:

Szulczewski, Piotr

Powiązania:

https://bibliotekanauki.pl/articles/2175554.pdf

Data publikacji:

2021

Wydawca:

Akademia Morska w Szczecinie. Wydawnictwo AMSz

Tematy:

seakeeping
numerical simulation
safety
safety of ships
ship stability

Opis:

During the currently ongoing development of methods for assessing the safety of ships, it is imperative that a compromise between the accuracy of the results and the accessibility of obtaining results is reached. This paper shows the calculations of a theoretical hull against damage stability regulations as included in SOLAS 2020, ICLL 66/88 as amended in 2003 and MARPOL 78. The rules included in the currently valid regulations require certain righting arm curve properties from vessels before and after potential damage, which does not pose a high difficulty level to engineers. However, for many engineers and scientists working with these rules, it is unclear what kind of behavior (particularly roll motion) these righting arm curve parameters correspond. In this paper, a correlation between the required GZ properties and the actual roll motion of a ship in waves, as calculated with the well-established method proposed by the ITTC, is revealed, and a comparison of the results to the currently in use regulations as well as comparison between the methods themselves is made. The comparison reveals the impact of GZ curve parameters on the roll motion of the ship.

Źródło:

Zeszyty Naukowe Akademii Morskiej w Szczecinie; 2021, 68 (140); 38--46
1733-8670
2392-0378

Pojawia się w:

Zeszyty Naukowe Akademii Morskiej w Szczecinie

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 81.

Tytuł:

Collapse modes of concrete reinforced square bridge piers under vehicle collision

Autorzy:

Zhou, Xiuneng
Xie, Zhongyou
Zhao, Zhixian
Li, Cheng

Powiązania:

https://bibliotekanauki.pl/articles/2086980.pdf

Data publikacji:

2022

Wydawca:

Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej

Tematy:

RC square pier
collapse mode
vehicle collision
numerical simulation

Opis:

In the field of engineering protection, there is a structural disaster named heavy vehicles impacting column structures. When a heavy truck collides with a reinforced concrete (RC) column at a high velocity, a large impact force generated makes perhaps the column fail and even collapse. Therefore, it is necessary to study the dynamic characteristics during such a disaster, which can provide some reference for structural design, optimization and protection. The RC column impacted by a vehicle could be simplified as a beam fixed at the bottom loaded by a concentrated force, whose deformation is controlled by shearing and bending. In the present work, the ultimate static forces corresponding to shearing and bending collapse are proposed based on theoretical analyses. The model validation is performed using the finite element approach and the theoretical analytical results are in good agreement with the finite element simulation results, which validates the present analytical model. Three cases are simulated by utilizing finite element code ABAQUS, which reveals that the approximate plateau collapse force keeps a long stage beyond the peak failure one. In addition, three collapse modes are observed based on the static force and deformation analysis, validating the present framework which can be used for routine pier design. The work can be extended to estimate collapse modes of building columns under a vehicle collision.

Źródło:

Journal of Theoretical and Applied Mechanics; 2022, 60, 3; 375--384
1429-2955

Pojawia się w:

Journal of Theoretical and Applied Mechanics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 82.

Tytuł:

Microscale laser shock imprinting of micro-molds with different sizes and shapes

Autorzy:

Yang, H.
Liu, K.
Liu, H.

Powiązania:

https://bibliotekanauki.pl/articles/174650.pdf

Data publikacji:

2018

Wydawca:

Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej

Tematy:

laser shock
imprinting
micro-mold
deformation depth
numerical simulation

Opis:

There are higher requirements for microstructures and high-precision components in microelectronics, photonics, sensors, optoelectronics and medical devices. For changing the traditional manufacturing methods with cumbersome process and complex equipment, researchers put forward a laser shock forming technique which can contribute to the metal forming with high precision and efficiency in recent years. So far, the laser shock forming needed high pulse energy and high energy. In this paper, nanosecond laser with high frequency and low pulse energy was adopted to make possible the aluminum foil forming on the copper micro-molds with different sizes and shapes. The deformations of aluminum foil were measured by SEM, optical profiler and AFM. Also, the deformation laws were analyzed by comparing imprinting results under different micro-molds. Lastly, stress distribution and deformation process of aluminum foil was investigated by numerical simulations.

Źródło:

Optica Applicata; 2018, 48, 4; 671-686
0078-5466
1899-7015

Pojawia się w:

Optica Applicata

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 83.

Tytuł:

Critical modeling issues of SiGe semiconductor devices

Autorzy:

Palankovski, V.
Selberherr, S.

Powiązania:

https://bibliotekanauki.pl/articles/308035.pdf

Data publikacji:

2004

Wydawca:

Instytut Łączności - Państwowy Instytut Badawczy

Tematy:

SiGe HBT
numerical simulation
band gap
mobility
small-signal simulation
S-parameters

Opis:

We present the state-of-the-art in simulation of silicon-germanium (SiGe) semiconductor devices. The work includes a detailed comparison of device simulators and current transport models. Among the critical modeling issues addressed in the paper, special attention is focused on the description of the anisotropic majority/minority electron mobility in strained SiGe grown on Si. We use a direct approach to obtain scattering parameters (S-parameters) and other derived figures of merit of SiGe heterojunction bipolar transistors (HBTs) by means of small-signal AC-analysis. Results from two-dimensional hydrodynamic simulations of SiGe HBTs are presented in good agreement with measured data. The examples are chosen to demonstrate technologically important issues which can be addressed and solved by device simulation.

Źródło:

Journal of Telecommunications and Information Technology; 2004, 1; 15-25
1509-4553
1899-8852

Pojawia się w:

Journal of Telecommunications and Information Technology

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 84.

Tytuł:

Simulation model of abrasive material motion
Imitacionnaja model dvizhenija abrazivnogo materiala

Autorzy:

Gorbunov, N.
Kovtanets, M.
Demin, R.

Powiązania:

https://bibliotekanauki.pl/articles/792972.pdf

Data publikacji:

2014

Wydawca:

Komisja Motoryzacji i Energetyki Rolnictwa

Tematy:

two-phase flow
abrasive material
simulation model
algorithm
numerical simulation
particle motion

Źródło:

Teka Komisji Motoryzacji i Energetyki Rolnictwa; 2014, 14, 1
1641-7739

Pojawia się w:

Teka Komisji Motoryzacji i Energetyki Rolnictwa

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

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Skocz do pozycji: 85.

Tytuł:

Detonation Characteristics of Gaseous Isopropyl Nitrate at High Concentrations

Autorzy:

Zeng, Linghui
Liang, Huimin
Zhang, Qi

Powiązania:

https://bibliotekanauki.pl/articles/27788043.pdf

Data publikacji:

2021

Wydawca:

Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego

Tematy:

isopropyl nitrate
detonation properties
detonation products
fuel-rich
numerical simulation

Opis:

Isopropyl nitrate (IPN) is a component of propellant fuel. High concentrations of IPN can still produce detonation. To date, very limited literature is available regarding high concentrations of IPN detonations. The detonation pressure is related to the equivalence ratio and density of IPN/air mixtures. These two factors have opposing effects on the detonation of an IPN/air mixture. The detonation characteristics of gaseous IPN/air mixtures at high concentrations (300-4000 g/m3) have been studied numerically. The results showed that when the IPN concentration is 300-600 g/m3, density played a dominant role on detonation. The maximum detonation pressure, 2.81 MPa, and the maximum detonation velocity, 1890 m/s, occurred at a concentration of 600 g/m3 (equivalence ratio Φ = 2.15). When the IPN concentration was increased from 300 to 600 g/m3, the peak overpressure and velocity increased by 19.6% and 6.2%, respectively. When the IPN concentration is higher than 600 g/m3, the equivalence ratio is extremely large and the detonation properties were seriously degraded. An analysis of the detonation products illustrated the burn-off rate of high concentrations of IPN and the influence of the detonation product CH3CHO. At a concentration of 600 g/m3, the IPN/air mixture can achieve optimal detonation properties and fuel economy.

Źródło:

Central European Journal of Energetic Materials; 2021, 18, 2; 245--270
1733-7178

Pojawia się w:

Central European Journal of Energetic Materials

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 86.

Tytuł:

Towards an Optimal Motor Mounting Bracket Using Topology Optimization Combined with Sustainability and Manufacturing Cost Analysis

Autorzy:

Fassi, Hicham Fihri
Aniyou, Hadji

Powiązania:

https://bibliotekanauki.pl/articles/27324206.pdf

Data publikacji:

2023

Wydawca:

Polska Akademia Nauk. Czasopisma i Monografie PAN

Tematy:

engine mount
topology optimization
numerical simulation
sustainability
manufacturing
costing analysis

Opis:

The engine is the most important component of a vehicle. It attaches to the main frame via the engine mounting bracket which supports weight and operating loads. The engine mount therefore plays a crucial role in the durability and comfort of the vehicle. This article contributes to the search for the most optimal model from the point of view of resistance, environmental impact, and manufacturing cost. This involves, on the one hand, optimizing the support by reducing its initial mass by 30%, and on the other hand, seeking suitable material and manufacturing process with the least environmental impact. To this end, topology optimization will be combined with an environmental assessment and a manufacturing cost analysis. Four materials will be tested and evaluated. Finally, a cost analysis will present a comparison between a conventional process and 3D printing.

Źródło:

Management and Production Engineering Review; 2023, 14, 4; 109--116
2080-8208
2082-1344

Pojawia się w:

Management and Production Engineering Review

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 87.

Tytuł:

Numerical Analysis of a DMA Epoxy-Carbon Composite Study
Analiza numeryczna metodyki badań DMA kompozytu epoksydowo-węglowego

Autorzy:

Kowaleczko, P.
Panas, A.
Nowakowski, M.

Powiązania:

https://bibliotekanauki.pl/articles/403771.pdf

Data publikacji:

2018

Wydawca:

Wojskowa Akademia Techniczna im. Jarosława Dąbrowskiego

Tematy:

composite material
DMA
numerical simulation
COMSOL
materiał kompozytowy
symulacja numeryczna

Opis:

The results of numerical simulations performed for Dynamic Mechanical Analysis (DMA) measurements of thermal and mechanical (or thermomechanical) properties performed on a model composite structure are presented herein. The simulated elastic response of an epoxy-carbon fibre composite specimen was analysed for a case by which the model specimen was subjected to three-point bending with a free support. The epoxy-carbon fibre composite studied as explained herein exhibited extreme differences between the elastic properties of the epoxy resin matrix and the carbon fibre reinforcement. In addition, the carbon fibre reinforcement was both internally and structurally anisotropic. The numerical simulations were performed to demonstrate a qualitative dependence of the DMA measurement results on a certain structure of the investigated specimen and to determine if the DMA results could be qualified as effective or apparent. A macro-mechanical model of the specimen was developed and the numerical calculations were performed by applying a COMSOL/M FEM (Finite Element Method) modelling software. The carbon fibre reinforcement was modelled with an orthotropic composite structure of planar laminar inclusions or as a disperse composite with circular inclusions. While modelling different characteristic dimensions of inclusions were taken into account. Representative material properties were assumed from the results of the appropriate experimental investigations and form certain literature reference data. The effect of the composite layer configuration and their characteristic dimensions on the evaluated model elastic modulus value was also studied. The numerical modelling results are in a qualitative agreement with the results of the DMA investigations performed on real composite. They also proved the effectiveness of the developed numerical simulation methodology in modelling of micro- and macromechanical phenomena occurring during the DMA study.
W pracy przedstawiono wyniki numerycznych badań symulacyjnych pomiaru właściwości cieplnomechanicznych (termomechanicznych) struktury kompozytowej. Uwagę skupiono na symulacji sprężystej odpowiedzi próbki kompozytu epoksydowo-węglowego poddanego analizie termomechanicznej DMA (Dynamic Mechanical Analysis) w trybie zginania z trójpunktowym swobodnym podparciem. Kompozyt epoksydowo-węglowy jako obiekt analizy charakteryzuje się bardzo dużą dysproporcją właściwości sprężystych materiału osnowy i wypełnienia. Dodatkowo cechy anizotropii wykazuje już sam materiał wypełnienia w postaci włókien węglowych. Celem wykonanych badań numerycznych było jakościowe określenie wpływu struktury na wyniki badań DMA i określenie możliwości zaklasyfikowania uzyskiwanych wyników jako właściwości efektywnych bądź pozornych. Do opracowania modelu makromechanicznego badanej próbki i przeprowadzenia obliczeń wykorzystano program modelowania MES COMSOL. Wypełnienie włóknami węglowymi modelowano za pomocą ortotropowych wtrąceń warstwowych lub kołowych o różnych wymiarach charakterystycznych. Reprezentatywne dane materiałowe przyjęto na podstawie wyników badań własnych i danych literaturowych. Zbadany został wpływ rozmieszczenia poszczególnych warstw oraz ich wymiaru charakterystycznego na określany z modelowej zależności moduł sprężystości E’.

Źródło:

Problemy Mechatroniki : uzbrojenie, lotnictwo, inżynieria bezpieczeństwa; 2018, 9, 4 (34); 101-112
2081-5891

Pojawia się w:

Problemy Mechatroniki : uzbrojenie, lotnictwo, inżynieria bezpieczeństwa

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 88.

Tytuł:

Study of a new type of Flettner rotor in merchant ships

Autorzy:

Li, Boyang
Zhang, Rui
Li, Yajing
Zhang, Baoshou
Guo, Chao

Powiązania:

https://bibliotekanauki.pl/articles/1573694.pdf

Data publikacji:

2021

Wydawca:

Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa

Tematy:

ship propulsion
flettner rotor
wind energy
rotating cylinder
numerical simulation

Opis:

Wind energy is a clean and renewable source of energy. This study seeks to explore the potential for utilising wind power for merchant ships. A new type of Flettner rotor (rotating cylinder) mounted on the superstructure of a ship is proposed and numerically simulated. The construction and installation of the rotating cylinder is designed and a numerical simulation of the ship-mounted cylinder is carried out, using the commercially available CFD code Ansys Fluent to obtain parameters such as lift and drag coefficient of the cylinder in different conditions. Specifically, it is found that the cylinder type superstructure can play a certain role in reducing the effect of friction by comparing traditional and cylindrical superstructures; the rotating cylinder can generate auxiliary thrust for the ship. After analysis, the wind speed around the cylinder and spin ratio will have a direct influence on its thrust effect; there is an inflection point in the lift coefficient with the increase of α; the thrust coefficient (8.63) reaches the maximum environmental wind speed at 10 m/s and spin ratio is 2.5. For the rotating cylinder, the greater the environmental wind, the greater the thrust contribution generated under the same spin ratio conditions. The maximum thrust can reach 750,000 N; the cylinder’s auxiliary propulsion contribution shows a better advantage in α = 2.0. The effective power generated by the cylinder reaches a maximum of 2,240 kW for environmental wind speed = 20 m/s and α = 1.0.

Źródło:

Polish Maritime Research; 2021, 1; 28-41
1233-2585

Pojawia się w:

Polish Maritime Research

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 89.

Tytuł:

Analizy numeryczne wybranych konstrukcji rozdrabniacza
Numerical and constructional analysis of grinders

Autorzy:

Macko, M.
Soboczyński, A.
Zybert, G.
Zgórski, Ł.
Jędrzejewski, Ł.
Wieczorek, P.
Wysocki, M.

Powiązania:

https://bibliotekanauki.pl/articles/2070317.pdf

Data publikacji:

2009

Wydawca:

Stowarzyszenie Inżynierów i Techników Mechaników Polskich

Tematy:

rozdrabniacz bijakowy
rozdrabnianie
symulacja numeryczna
hammer mill
milling
numerical simulation

Opis:

Praca dotyczy zagadnień konstrukcyjnych rozdrabniaczy bijakowych oraz analiz numerycznych przeprowadzonych w środowisku CAD/CAE. Przedstawiono wybrane wyniki procesu dla wybranego zakresu prędkości obrotowych. Wyniki uzyskane w badaniach symulacyjnych porównano w dalszym etapie z wynikami badań laboratoryjnych.
The CAD/CAE emdronment was used for checking some constructional issues and numerical analysis of hammer mills. Results for a selected rangę of rotational yelocity arę presented. The simulation results were compared with those obtained in laboratory-scale tests.

Źródło:

Inżynieria i Aparatura Chemiczna; 2009, 2; 92-93
0368-0827

Pojawia się w:

Inżynieria i Aparatura Chemiczna

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 90.

Tytuł:

Symulacje numeryczna procesu koalescencji w emulsjach spożywczych
Numerical simulations of coalescence proces in food emulsions

Autorzy:

Sęk, J.
Strzelecka, A.

Powiązania:

https://bibliotekanauki.pl/articles/2071653.pdf

Data publikacji:

2011

Wydawca:

Stowarzyszenie Inżynierów i Techników Mechaników Polskich

Tematy:

emulsja
koalescencja
śmietankowanie
symulacja numeryczna
emulsions
coalescence
creaming
numerical simulation

Opis:

Badano numerycznie proces koalescencji i śmietankowania w emulsjach. Stworzono modele numeryczne układów dwufazowych zawierających regularnie rozmieszczone krople fazy rozproszonej. Przeprowadzono symulacje zachowania się takich rojów w warunkach różnych wartości sił masowych i przy różnej średnicy kropel. Wykazano zgodność wyników uzyskanych za pomocą modeli numerycznych z wartościami wynikającymi z zależności teoretycznych. Stwierdzono również różny przebieg procesów śmietankowania i koalescencji w zależności od warunków przepływu.
Coalescence and creaming of emulsions were investigated numerically. Numerical models of two-phase systems containing regularly distributed droplets of dispersed phase were created. Numerical simulation of flow and behavior of those systems of droplets were performed for different values of body forces and for different droplet diameter. It was proved that the numerical models were compatible with the theoretical equations. A different course of coalescence and creaming process was observed depending on flow conditions.

Źródło:

Inżynieria i Aparatura Chemiczna; 2011, 1; 41-42
0368-0827

Pojawia się w:

Inżynieria i Aparatura Chemiczna

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 91.

Tytuł:

Modelowanie numeryczne rozwoju delaminacji w warunkach obciążeń cyklicznych
Numerical simulation of delamination growth due to cyclic loading

Autorzy:

Szeląg, D.
Bajurko, P.
Czarnocki, P.

Powiązania:

https://bibliotekanauki.pl/articles/213296.pdf

Data publikacji:

2011

Wydawca:

Sieć Badawcza Łukasiewicz - Instytut Lotnictwa

Tematy:

modelowanie numeryczne
delaminacja
badania zmęczeniowe
numerical simulation
delamination
cycling loading

Opis:

Przedstawiono uproszczoną procedurę numerycznego symulowania rozwoju delaminacji z wykorzystaniem MES, w warunkach 1 sposobu pękania, pod działaniem obciążenia cyklicznego. Uproszczenie polegało na ograniczeniu procesu degradacji zmęczeniowej materiału do jednego elementu, bezpośrednio sąsiadującego z czołem rozwarstwienia. Otrzymane wyniki w niewielkim stopniu odbiegały od wyników badań zmeczeniowych.
Simplified procedure taking advantage of FEM for simulation of delamination growth due to Mode I cycling loading is presented. The simplification consisted in restricting effect of fatigue load to one element that was next to the dealmination front only. The discrepancy between the numerical and experimental results was not significant.

Źródło:

Prace Instytutu Lotnictwa; 2011, 12 (221); 189-193
0509-6669
2300-5408

Pojawia się w:

Prace Instytutu Lotnictwa

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 92.

Tytuł:

Composite-polymer materials for energy-absorbing structures

Autorzy:

Barnat, W.
Niezgoda, T.
Ochelski, S.

Powiązania:

https://bibliotekanauki.pl/articles/246205.pdf

Data publikacji:

2009

Wydawca:

Instytut Techniczny Wojsk Lotniczych

Tematy:

energy absorption structures
safety
composites
numerical simulation
energy absorption investigations

Opis:

On the basis of the results obtained from our own experimental investigations of energy- absorbing elements, the influence of the given factors on absorbed energy (WEA) was determined. The objects of the research were the samples made of epoxy composites reinforced with glass fibres formed in roving, roving stripes and glass mat as well as with carbon fibres formed in roving and carbon roving stripes. To investigate the capability of hitting energy absorption of the samples in the shape of tubes, the truncate cones and in the shape of a thin cuboid were taken under consideration. The sample in the shape of tubes, wavy coats and thin cuboids with angle 45° (on one edge), play the role of the initiator of progressive destruction process. The composites matrix was taken into account during investigations: epoxy, the vinyl-esters, polyetheretherketones, reinforced with carbon and glass fibres with different structures of the samples. The influence of the sample geometry and the orientation of the layers in carbon / epoxide and the ar amid / the epoxide composites on the WEA absorption value were presented in the papers. The comparison of the structures made f rom single elements with relevant structures of four elements shows that absorbed energy is accumulating. In this case the relative absorbed energy remains at the similar level.

Źródło:

Journal of KONES; 2009, 16, 1; 21-34
1231-4005
2354-0133

Pojawia się w:

Journal of KONES

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 93.

Tytuł:

The innovations in description of propriety of structures the hyper-elastic materials

Autorzy:

Żach, P.

Powiązania:

https://bibliotekanauki.pl/articles/247644.pdf

Data publikacji:

2010

Wydawca:

Instytut Techniczny Wojsk Lotniczych

Tematy:

plastics
hyperelastic materials
numerical simulation
identification of propriety elastomers materials

Opis:

The hyper-elastic materials e.g.: the elastomers, frothed structures PUR about open and closed pores, the materials using the matrix of natural rubber materials whether as well as synthetic the gels be practical used in different engineer applications from over 30 year s. They really several summers and intensive works on field of materiał engineering made possible extension the spectres of uses as well as the utilization of elastomers compositions. In this paper, will be presented built methodology of elasticity propriety materials with large deformation. In article be become presented method of identification and description of hyper-elastic materials from special return on numeric models the attention. Quantitative analysis be becomes executed in support about executed experimental investigations. The numeric permissive on comparison of received conception of description of hyper-elastic material worked out in support about theoretical foundations with results of experimental investigations analyses be become executed.

Źródło:

Journal of KONES; 2010, 17, 3; 533-538
1231-4005
2354-0133

Pojawia się w:

Journal of KONES

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 94.

Tytuł:

Numerical simulation the finite element method (FEM) of stress and strain for the chosen coatings TBCs on turbine blades loaded with laser impulses

Autorzy:

Kosiuczenko, K.
Napadłek, W.

Powiązania:

https://bibliotekanauki.pl/articles/248121.pdf

Data publikacji:

2012

Wydawca:

Instytut Techniczny Wojsk Lotniczych

Tematy:

superalloy ŻS6K-WI
laser ablation
numerical simulation MES

Opis:

This paper presents the results of laser ablation the barrier coating TBCs (Al2O3, ZrO2) generated on aircraft engine turbine blade made for nickel base alloy ŻS6K-- WI. Authors used neodymium impulse Nd: YAG laser, radiation with a wavelength of 1064 nm. In parallel with the laboratory experiment was performed numerical simulation of laser ablation. FEM simulation results were used for to choose the relevant laser parameters (impulse duration, impulse shape and course in time, power density) and to identify the temperature distribution heat fluxes and the state of stress and strain in the critical zones of the barrier coating TBCs. The simulation was carried out using the finite element method program LS-Dyna. On the basis of numerical simulation shown the influence of the impact layer TBCs as a thermal insulation and shown place the appearance of destructive deformation. Defined distributed tension as a function of time and estimated time destruction parts the barrier layer during the laser ablation micromachining. Model 3D of the engine turbine blades DV - 2, Analyzed piece of blade, physical model, temperature maps, maps of the reduced stress are presented in the paper

Źródło:

Journal of KONES; 2012, 19, 1; 183-186
1231-4005
2354-0133

Pojawia się w:

Journal of KONES

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 95.

Tytuł:

Natural convection from four circular cylinders in across arrangement within horizontal annular space

Autorzy:

Laidoudi, Houssem

Powiązania:

https://bibliotekanauki.pl/articles/387589.pdf

Data publikacji:

2020

Wydawca:

Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej

Tematy:

natural convection
multiple cylinders
annular space
heat transfer
numerical simulation

Opis:

Numerical investigation is accomplished to study the roles of governing parameters of natural convection on the fluid motion and heat transfer rate of four heated circular cylinders placed inside a circular enclosure of cold surface. The cylinders are positioned in across arrangement. The representative results are obtained within the ranges of initial conditions as: Prandtl number (Pr = 7.1 to 1000) and Rayleigh number (Ra = 103 to 105). The average Nusselt number of each inner cylinder is computed. The effects of thermal buoyancy strength on the fluid motion and temperature are also illustrated. It was found that the heat transfer rate of cylinders depends significantly on the position inside the enclosure. Moreover, the role of Prandtl number on flow and thermal patterns is negligible. The values of Nusselt number are also given, which can be useful for some engineering applications.

Źródło:

Acta Mechanica et Automatica; 2020, 14, 2; 98-102
1898-4088
2300-5319

Pojawia się w:

Acta Mechanica et Automatica

Dostawca treści:

Biblioteka Nauki

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Skocz do pozycji: 96.

Tytuł:

Temperature-dependent Shock Initiation of CL-20-based High Explosives

Autorzy:

Pi, Z.
Chen, L.
Wu, J.

Powiązania:

https://bibliotekanauki.pl/articles/358764.pdf

Data publikacji:

2017

Wydawca:

Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego

Tematy:

CL-20
shock initiation
heated explosive
phase transitions
numerical simulation

Opis:

To investigate the effects of temperature on the shock initiation characteristics of hexanitrohexaazaisowurtzitane (CL-20), shock initiation experiments on heated C-1 explosive (94% epsilon phase CL-20, and 6% binder, by weight) were performed at temperatures of 20 °C, 48 °C, 75 °C, 95 °C, 125 °C, 142 °C, and 175 °C. An explosive driven flyer device was used to initiate the C-1 charges and manganin pressure gauges were embedded in the C-1 specimen to record the pressure changes with time. Our results show that C-1 becomes more sensitive as the temperature is increased from 20 °C to 95 °C. The ε to γ phase transition in CL-20 occurs at 125 °C; C-1 with CL-20 in the γ phase at 142 °C is less shock sensitive than C-1 with CL-20 in the ε phase at 95 °C or 75 °C. Compared with C-1 at 142 °C, C-1 at 175 °C shows a dramatic increase in shock sensitivity. An ignition and growth reactive flow model was used to simulate the shock initiation of C-1 at various temperatures, and the parameters were obtained by fitting the experimental data. With this parameter set, the shock initiation characteristics of C-1 for temperatures between 20 °C and 175 °C can be derived.

Źródło:

Central European Journal of Energetic Materials; 2017, 14, 2; 361-374
1733-7178

Pojawia się w:

Central European Journal of Energetic Materials

Dostawca treści:

Biblioteka Nauki

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Skocz do pozycji: 97.

Tytuł:

Numerical analysis on Rib-tubes of seawater open rack vaporizer with the spoiler lever

Autorzy:

Su, H.
Yu, S.
Fan, J.
Xing, W.

Powiązania:

https://bibliotekanauki.pl/articles/258810.pdf

Data publikacji:

2017

Wydawca:

Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa

Tematy:

spoiler lever
Open Rack Vaporizer(ORV)
Rib-tubes
numerical simulation

Opis:

In order to explore a more reasonable structure and operating parameter, guide the design and improve the gasification of seawater Open Rack Vaporizer (ORV), Research on the rules of seawater that flows and heat transfer in the ORV tube was studied in this paper. By simplifying the model, heat transfer tube model with spoiler lever was obtained and simulated, the distribution of temperature field, gas ratio, velocity field and press field in rib tube were analyzed, and different inlet velocity of LNG, roughness of the tube wall both effected on the overall gasification, the results shows that the actual gasification efficiency from heat transfer tube is higher than normal, small difference of gas ratio outlet, velocity and temperature are both lower, LNG could be easer gasified at operating temperature between -162°C~+3°C than that between -162°C~+0°C.

Źródło:

Polish Maritime Research; 2017, S 2; 14-21
1233-2585

Pojawia się w:

Polish Maritime Research

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 98.

Tytuł:

Numerical simulation of solid-fluid 2-phaseflow of cutting system for cutter suction dredgers

Autorzy:

Zhang, M.
Fan, S.
Zhua, H.
Han, S.

Powiązania:

https://bibliotekanauki.pl/articles/259081.pdf

Data publikacji:

2018

Wydawca:

Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa

Tematy:

numerical simulation
solid-fluid
DPM
cutting system
cutter suction dredger

Opis:

The study of the flow characteristics of the solid-fluid two phase flow in the cutter suction dredger is very important for exploring the slurry formation mechanism and optimizing the operational parameters. In this study, standard k-ε model and Multiple Reference Frame are applied to numerically simulate flow field in and around the cutting system, then with the steady convergent result of the simulation as the initial condition, Discrete Phase Mode is used to solve the particle motion equation by fully coupling the continuous phase and the particles . The influence of suction flow velocity and cutter’s rotating speed on particles suction are analyzed, and effectively suctioned particles numbers are also quantitatively studied. The simulation result shows that the DPM model is able to simulate the movement of particles in and around the cutter suction dredger’s cutting system, in the fluid flow filed velocity vector and pressure distribution on different planes show different characteristics, and under higher suction velocity and lower cutter rotating speed more particles are suctioned into the suction inlet. The results can help better understand flow characteristics of solidfluid 2-phase-flow of cutter suction dredger’s cutting system, and provide theoretical support for relative system design and operational parameters optimization.

Źródło:

Polish Maritime Research; 2018, S 2; 117-124
1233-2585

Pojawia się w:

Polish Maritime Research

Dostawca treści:

Biblioteka Nauki

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Skocz do pozycji: 99.

Tytuł:

Influence of the atmospheric turbulence on the accuracy of the missile targeting

Autorzy:

Kowaleczko, G.
Kaźmierczak, R.

Powiązania:

https://bibliotekanauki.pl/articles/950099.pdf

Data publikacji:

2017

Wydawca:

Instytut Techniczny Wojsk Lotniczych

Tematy:

missile dynamics
stochastic turbulence
numerical simulation
dynamika pocisku
symulacja numeryczna

Opis:

The article presents results of simulation of 6-DOF motion for a missile subjected to atmospheric turbulences. Therefore, an applied mathematical model of motion includes description of stochastic turbulences influencing on missile flight. Both models of the motion as well as of turbulences are shortly presented. Model validity was assessed by comparing the calculation results with the data recorded during shooting on the range. Result of series of simulations allows determining the missile sensitivity to this case of disturbances. Exemplary results of simulations are shown. The turbulence model assumes that the wind is dependent on time and space. This assumption is based on the Taylor's "frozen turbulence" hypothesis. The advection velocity of the turbulence is much greater than the velocity scale of the turbulence itself. The velocity has two component. In the article, the first component is omitted and the second is treated as the stochastic process representing atmospheric turbulence. To describe this turbulence Shinozuka's method was applied. Mathematical description of the missile motion, equations of translatory motion, External forces end moments, model of the turbulence are presented in the article.

Źródło:

Journal of KONES; 2017, 24, 1; 211-222
1231-4005
2354-0133

Pojawia się w:

Journal of KONES

Dostawca treści:

Biblioteka Nauki

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Skocz do pozycji: 100.

Tytuł:

The Effect of the Use of Technological Lubricants Based on Vegetable Oils on the Process of Titanium Sheet Metal Forming

Autorzy:

Więckowski, W.
Dyja, K.

Powiązania:

https://bibliotekanauki.pl/articles/353140.pdf

Data publikacji:

2017

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

sheet metal forming
tribological system
technical lubricant
numerical simulation (FEM)

Opis:

The paper evaluates the drawability of titanium sheet metal Grade 2, with the focus on friction conditions that are present in the sheet metal forming process. The study aims to present the results of the examinations of the friction coefficient during a strip drawing test. The focus of the experiment was on lubricants based on vegetable oils i.e. rapeseed oil, sunflower oil and olive oil. Boric acid was used to improve the lubricating properties of vegetable oils. The results of numerical simulations of the process of forming a cover with stiffening components made of grade 2 titanium sheet metal was also presented. The numerical simulation was carried out using the FEM method with PAMStamp 2G software. The effect of conditions of friction between the sheet metal and tool parts and pressure force of the blank holder on the forming process were investigated. Numerical calculations were performed with consideration for the phenomenon of material strain hardening and anisotropy of plastic properties of the sheet metal formed. The analysis of the deformations and reduction in wall thickness of the drawn parts can be used for determination of the effect of changes in selected parameters on the process of drawn part forming. The quality of drawn parts was assessed based on the shape inaccuracy determined during simulation of forming. The inaccuracy depended on the conditions of the process and strength properties of the titanium sheet metal.

Źródło:

Archives of Metallurgy and Materials; 2017, 62, 2A; 489-494
1733-3490

Pojawia się w:

Archives of Metallurgy and Materials

Dostawca treści:

Biblioteka Nauki

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