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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
Artykuł
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
Artykuł
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
Artykuł
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
Artykuł
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
Artykuł
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
Artykuł
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
Artykuł
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
Artykuł
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
Artykuł
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
Artykuł
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
Artykuł
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
Artykuł
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
Artykuł
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
Artykuł
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
Artykuł
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
Artykuł
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
Artykuł
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
Artykuł
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
Artykuł
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
Artykuł
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
Artykuł
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
Artykuł
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
Artykuł
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
Artykuł
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
Artykuł
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