Informacja

Drogi użytkowniku, aplikacja do prawidłowego działania wymaga obsługi JavaScript. Proszę włącz obsługę JavaScript w Twojej przeglądarce.

English (EN)·Polski (PL)·Yкраїнський (UK)
Przejdź do strony domowej biblioteki Centralna Biblioteka Wojskowa Link otwiera się w nowym oknie Logo biblioteki Prolib Integro - strona głównaCentralna Biblioteka Wojskowa

Wyszukujesz frazę "state stress" wg kryterium: Temat

  Lista filtrów
Wyrównaj
Wyświetlanie 1-25 z 123
Tytuł:
Technological Forecasting of Deformations in Flat Parts
Autorzy:
Ivanova, Tatiana N.
Biały, Witold
Fries, Jiri
Nordin, Victor
Powiązania:
https://bibliotekanauki.pl/articles/2064652.pdf
Data publikacji:
2020
Wydawca:
STE GROUP
Tematy:
deformation
state stress
stress diagram
residual stresses
stress formation
grinding
Opis:
The deformation of a part occurring in the process of grinding directly influences its exploitation and quality parameters. The instability of shape and size, which occurs due to an imbalance of residual stress, can be the one of the major causes of deformation of a part. The decrease in stress slows down the deformation process. Considering the regularities of heat source intensity dependence on the grinding modes, it can be asserted that with increasing grinding depth and grinding wheel hardness, the value increases and it decreases with a growth in a speed of the part and the use of cooling. The higher the heat removal is and the better lubricant properties of the liquid are, the more significant the decrease in is. Changing these values allows regulation of the residual stresses. As a result of the research on determination of deformations, it is recommended to reduce thermal deformations by considering the geometric size of a plate to be machined, linear expansion coefficient of plate material and an allowance for nonflatness from thermal deformations. The value of nonflatness from thermal deformations is directly proportional to linear expansion coefficient of plate material and its square overall dimensions. At the same time, the value of nonflatness is inversely proportional to the plate thickness.
Źródło:
Multidisciplinary Aspects of Production Engineering; 2020, 3, 1; 1--12
2545-2827
Pojawia się w:
Multidisciplinary Aspects of Production Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ocenka deformirujemosti zagotovok v processe valcovki
Estimation of deformability billets during rolling
Autorzy:
Gun'ko, I.
Dobranuk, Y.
Powiązania:
https://bibliotekanauki.pl/articles/78062.pdf
Data publikacji:
2013
Wydawca:
Komisja Motoryzacji i Energetyki Rolnictwa
Tematy:
stress-strain state
cylindrical billet
stress state parameter
deformability
rolling
trajectory deformation
Opis:
Forming analyzed and solved the problem of determining the stress-strain state of a cylindrical billet during rolling using simulation in the software package DEFORM 3D. Patterns of forming and distribution of the accumulated damages to the billet during deformation is received. A study of dangerous, in terms of damage accumulation, points billet is performed. For this it was constructed and analyzed the trajectory of deformation at these points of the billet.
Źródło:
Motrol. Motoryzacja i Energetyka Rolnictwa; 2013, 15, 4
1730-8658
Pojawia się w:
Motrol. Motoryzacja i Energetyka Rolnictwa
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Complete solution for the saturated slopes in the limit stress state
Autorzy:
Batog, A.
Stilger-Szydło, E.
Powiązania:
https://bibliotekanauki.pl/articles/241498.pdf
Data publikacji:
2003
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
saturated slopes
limit stress state
Opis:
Complete solutions of saturated slopes in the limit state, in the aspects of statics and kinematics, are presented. The proposed methods can be applied to the calculation of stress fields and velocity fields and the esti-mation of the limit load for two basic (associated and non-associated with linear Mohr-Coulomb yield condition) flow rules. Samples of calcu-lations for diverse saturation conditions appeared in slopes are included. The proposed methods will contribute to the extension of the use of limit state methods in engineering practice.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2003, 50, 2; 85-106
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Anomalous drill-core parting in the sediments of the Upper Silesian basin
Autorzy:
Kožušníková, A.
Fialová, V.
Hoch, I.
Powiązania:
https://bibliotekanauki.pl/articles/191518.pdf
Data publikacji:
2003
Wydawca:
Polskie Towarzystwo Geologiczne
Tematy:
core
anomalous parting
stress state
Opis:
Anomalous jointing of drillcores is sometimes observed in prospect boreholes in the Upper Silesian basin. The drillcore is jointed into discs, slices or porringers that are not resemblant to natural jointing. This occurs in various types of sediments, but especially in brittle rocks. Orientation of jointing planes is perpendicular to the borehole axis and does not depend on the distance from the front of the core run. Anomalous jointing reflects locally increased stress in the layer.
Źródło:
Annales Societatis Geologorum Poloniae; 2003, 73, No 2; 139-143
0208-9068
Pojawia się w:
Annales Societatis Geologorum Poloniae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
FEM simulation of the tube rolling process in Diescher’s mill
Autorzy:
Pater, Z.
Tofil, A.
Powiązania:
https://bibliotekanauki.pl/articles/102656.pdf
Data publikacji:
2014
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
tube rolling
FEM
state of stress and strain
Opis:
This paper deals with the issue of numerical modelling of the piercing process of a thick–walled bush in a two-rolled skew rolling mill, equipped with guiding devices of Diescher’s type. After a short characteristic of the subject matter, the developed geometric model of the process was discussed, with taking kinematics of tools movement and thermal phenomena present in metal during forming into consideration. Next, the results of calculations were presented in a form of fields of strain, damage criterion and temperature. Distributions of force parameters acting on particular tools during the process of bush rolling were also given.
Źródło:
Advances in Science and Technology. Research Journal; 2014, 8, 22; 51-55
2299-8624
Pojawia się w:
Advances in Science and Technology. Research Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Some aspects of dynamic riveting simulations
Autorzy:
Szymczyk, E.
Jachimowicz, J.
Puchała, K.
Powiązania:
https://bibliotekanauki.pl/articles/248006.pdf
Data publikacji:
2012
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
riveting
dynamic simulation
residual stress state
Opis:
Riveting is a commonly used (especially in aircraft structures) method of joining metal and composite components. The methods of forming solid shank rivets can be classified in two types: static and dynamic. The static method is the most efficient one. Regrettably, its application is limited. A popular upsetting tool used in an aircraft is a pneumatic riveter. The rivet driving requires a few hammer strokes. The total stress in a riveted joint depends on the residual and applied stress. Residual post-riveting stress fields are widely accepted to have a beneficial influence on the fatigue life of aircraft structures. The analysis is carried out for a solid mushroom rivet (made of PA25 alloy) joining two sheets (made of 2024T3 alloy). Nonlinear dynamic simulations of the upsetting process are carried out. Simulation of the riveting process is significantly influenced by a material model. The numerical calculations are performed for three different cases of upsetting described by the formed rivet head diameters 1.4d, 1.5d and 1.6d, respectively. The rivet head diameter and, consequently, the residual stress state depend on hammer stroke energy. It has a significant influence on a plastic region around the rivet hole, whereas the influence of a number of strokes can be neglected. The strain rate in both local and global (average) formulation is analysed in the paper. For one hammer stroke, the global strain rate of the rivet shank is about 1.0 thousand per second. The local strain rate is about two times greater than the global one, so a strain rate factor has an effect on the residual stress state. For a few hammer strokes, the strain rate is lower than for one stroke; however, it increases a little in each stroke. The hole deformation can be treated as a function of the internal energy of the sheet. The lower total energy of the part the greater influence of the strain rate on the internal energy is observed.
Źródło:
Journal of KONES; 2012, 19, 1; 423-430
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dynamic stress concentration at the boundary of an incision at the plate under the action of weak shock waves
Autorzy:
Mikulich, O.
Shvabyuk, V.
Sulym, H.
Powiązania:
https://bibliotekanauki.pl/articles/386957.pdf
Data publikacji:
2017
Wydawca:
Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Tematy:
stress state
plate
incision
weak shock wave
Opis:
This paper proposes the novel technique for analysis of dynamic stress state of multi-connected infinite plates under the action of weak shock waves. For solution of the problem it uses the integral and discrete Fourier transforms. Calculation of transformed dynamic stresses at the incisions of plates is held using the boundary-integral equation method and the theory of complex variable functions. The numerical implementation of the developed algorithm is based on the method of mechanical quadratures and collocation technique. For calculation of originals of the dynamic stresses it uses modified discrete Fourier transform. The algorithm is effective in the analysis of the dynamic stress state of defective plates.
Źródło:
Acta Mechanica et Automatica; 2017, 11, 3; 217-221
1898-4088
2300-5319
Pojawia się w:
Acta Mechanica et Automatica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Локальная устой чйвость плоскйх многограннйков сетчатых куполов
Local stability of flat polyhedrons of mesh domes
Autorzy:
ДРАГАН, В. И.
ГЛУШКО, К. К
Powiązania:
https://bibliotekanauki.pl/articles/1203945.pdf
Data publikacji:
2016
Wydawca:
Centrum Rzeczoznawstwa Budowlanego Sp. z o.o.
Tematy:
stress-strain state
fragment
mesh dome
Opis:
The dependences for determining the stress-strain state of a fragment of a mesh dome. These formulas are valid for the case of constant-largest hub load on a mesh dome. Experimentally determined tense and strained state of the dome fragment. The proposed method has a good agreement with the experimental results.
Źródło:
Modern Engineering; 2016, 1; 82-93
2450-5501
Pojawia się w:
Modern Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical analysis of the stress-strain state of a rope strand with linear contact under tension and torsion loading conditions
Autorzy:
Kalentev, E.
Václav, S.
Božek, P.
Tarasov, V.
Korshunov, A.
Powiązania:
https://bibliotekanauki.pl/articles/102692.pdf
Data publikacji:
2017
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
numerical analysis
stress-strain state
rope
Opis:
The paper presents the results of a numerical analysis of the stress-strain state of a rope strand with linear contact under tension and torsion loading conditions. Calculations are carried out using the ANSYS software package. Different approaches to calculation of the stress-strain state of ropes are reviewed, and their advantages and deficiencies are considered. The analysis of the obtained results leads us to the conclusion that the proposed method can be used in engineering calculations.
Źródło:
Advances in Science and Technology. Research Journal; 2017, 11, 2; 231-239
2299-8624
Pojawia się w:
Advances in Science and Technology. Research Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Use of 3D printing technology in the aviation industry on an example of numerical experimental stress state analysis of unmanned aerial vehicle wing
Autorzy:
Święch, Ł.
Bendarz, A.
Powiązania:
https://bibliotekanauki.pl/articles/246287.pdf
Data publikacji:
2017
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
DIC
3d printing
FFF
stress state
UAV
Opis:
The article presents the results of static tests performed on the primary support structures of a TWISST-ter unmanned aircraft constructed using additive manufacturing techniques commonly known as 3D printing. The primary goal of the experiment was determining the material effort of the structure in order to assess the feasibility of such an engineering solution in terms of material mechanics. Considering the fact that the properties of 3D printed elements are not widely known, both destructive experimental methods and finite element methods were used. During the experimental trails, the ARAMIS deformation measurement system, based on digital three-dimensional image correlation, was used. The results of this experiment allowed for the calibration of the numerical model as achieving convergence with experimentally determined strain fields. This approach ensured the correctness of the numerical determined stress state. Based on the results of the study, the necessary design improvements were implemented and a general conclusion was formed regarding of the numerical analysis of structures made through 3D printing.
Źródło:
Journal of KONES; 2017, 24, 4; 327-334
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modelling of impulse load influence on the stress state of foam materials with positive and negative poisson’s ratio
Autorzy:
Sulym, Heorhiy
Mikulich, Olena
Shvabyuk, Vasyl
Powiązania:
https://bibliotekanauki.pl/articles/387508.pdf
Data publikacji:
2020
Wydawca:
Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Tematy:
stress state
foam
poisson’s ratio
cosserat elasticity
Opis:
The influence of impulse load applied for different duration on the distribution of normalised dynamic radial stresses in positive and negative Poisson’s ratio medium was investigated in this study. For solving the non-stationary problem in the case of plane deformation for structurally inhomogeneous materials, the model of Cosserat continuum was applied. This model enables accounting for the influence of shear-rotation deformation of micro-particles of the medium. In the framework of Cosserat elasticity, on applying the Fourier transforms for time variable and developing the boundary integral equation method, solving of the non-stationary problem reduces to the system of singular integral equations, where the components that determine the influence of shear-rotation deformations are selected. The numerical calculations were performed for the foam medium with positive and negative Poisson’s ratio for different values of time duration of impulse. Developed approach can be used to predict the mechanical behaviour of foam auxetic materials obtained at different values of a volumetric compression ratio under the action of time variable load based on analysis of the dis-tribution of radial stresses in foam medium.
Źródło:
Acta Mechanica et Automatica; 2020, 14, 2; 79-83
1898-4088
2300-5319
Pojawia się w:
Acta Mechanica et Automatica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Description of strength of wood composite in compound state of load
Autorzy:
Kyzioł, L.
Powiązania:
https://bibliotekanauki.pl/articles/950148.pdf
Data publikacji:
2017
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
compound state of stress
modified wood
effort criterion
strengthening of the material
Opis:
All constructions are subject to the most compound loads and therefore a suitable effort hypothesis should be used for their calculation. For anisotropic materials, a hypothesis should be used to describe the properties of such materials. In the work have been shown the strength of the layers composite on the example of construction wood in a compound stress state. Wood composite is an orthotropic material. Wood is composed of alternating layers of soft wood and hard wood. Single layers are monotropic material. The use of a stress hypothesis, which describes the strength of an orthotropic material, requires will make an investigation. Studies is purposed to determine the tensile strength along and across the fibres. The compressive strengths along and across the fibres and the shear strength. Particularly the determination of shear strength requires special tooling so that in the case of flat samples in the measuring part it is possible to determine the shear stresses. Therefore, a research stand was designed and constructed. Known stress hypotheses for anisotropic materials have been analysed. The analysis showed that the strength of the wood composite could be described by the Tai-Wu stress hypothesis. Based on the results of the research, numerical calculations were performed. Calculations allowed determining the distribution of stresses in the sample measuring part. The results tests and numerical calculations have shown that obtaining a homogeneous stress (shear) condition for anisotropic materials is very difficult. Wood belongs to materials whose mechanical properties depend on many parameters, so the description of the effort of this material is a compound issue. Studies have shown that wood reinforcement by polymer saturation is best suited to the compressed loaded structures.
Źródło:
Journal of KONES; 2017, 24, 3; 161-165
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Determination of stress state based on well logging data and laboratory easurements – a CBM well in the southeastern part of the Upper Silesian Coal Basin (Poland)
Autorzy:
Kępiński, Michał
Powiązania:
https://bibliotekanauki.pl/articles/184365.pdf
Data publikacji:
2020
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
Mechanical Earth Model
Upper Silesian Coal Basin
stress state
Opis:
The main objective of this study is to present calculation methods of horizontal stress profiles, taking into account the stress boundaries model, poro-elastic horizontal strain model and the effective stress ratio approach, using calibration with wellbore failure. The mechanical earth model (MEM) parameters from log measurements and well testing data were estimated for a well located in the southeastern part of the Upper Silesian Coal Basin. Log-derived horizontal stresses of the well are commonly treated as the final product of geomechanical modeling in oil and gas practices. A less popular method for estimating horizontal stresses is based on Kirsch equations juxtaposed with compressional and tensile failure observed on a micro-imager or six-arm caliper. Using this approach, horizontal stresses are determined based on the fact that when hoop stresses exceed the formation’s tensile strength, tensile fractures are created, and when those stresses exceed the compressive strength of the formation, breakouts can be identified. The advantage of this method is that it can be run without in situ stress measurements. The presented workflow is recommended every time there is an image log and dipole sonic measurement in the available dataset, both being necessary to observe the failure zones and MEM.
Źródło:
Geology, Geophysics and Environment; 2020, 46, 2; 77-92
2299-8004
2353-0790
Pojawia się w:
Geology, Geophysics and Environment
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Partial cases of stressed-deformed condition of casing and pump compressor pipes
Autorzy:
Vasylyshyn, Vitalii
Taras, Iryna
Bekish, Iryna
Kornuta, Olena
Kornuta, Volodymyr
Powiązania:
https://bibliotekanauki.pl/articles/409894.pdf
Data publikacji:
2020
Wydawca:
STE GROUP
Tematy:
tubing
stress-strain state
fatigue life
tightening torque
Opis:
Threaded joints are the most technological for piling up in the fields. However, violations of standard threaded joints account for 70% of all complications in pipe processing and production. These malfunctions result in significant material losses, reduced well productivity, and contamination of the wells and environmental pollution. Particularly acute is the loss of these sealed joints during exploration and development of gas and gas condensate fields. The necessary increase in volumes and intensification of hydrocarbon energy production is envisaged by the increase of drilling depth, construction of slopes and horizontal wells. Horizontal drilling and fracturing are used to produce shale gas. The efficiency and safety of the operation of oil and gas wells in complex mining and technical conditions depend on the quality and reliability of casing and pumping columns, which requires the modernization of machinery and technology for the installation of wells. The most technological for column fitting in the fisheries sector is threaded joints. However, breach of standard threaded connections causes 70% of all complications with pump housings and columns. This leads to significant material losses, reduced production of raw materials, contamination of the interior and the environment. Therefore, the urgent task is to improve the threaded joints by increasing their reliability and efficiency under heavy workloads.
Źródło:
Management Systems in Production Engineering; 2020, 2 (28); 97-103
2299-0461
Pojawia się w:
Management Systems in Production Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wpływ temperatury na stan naprężenia i odkształcenia w otoczeniu komory siłowni elektrowni "Porąbka-Żar"
The relationship between temperature and stress and strain state in the vicinity of the chamber "Porąbka-Żar" power station
Autorzy:
Domańska, D.
Gruszka, R.
Powiązania:
https://bibliotekanauki.pl/articles/350000.pdf
Data publikacji:
2005
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
wyrobisko wielkogabarytowe
temperatura
stan naprężenia
large chamber
temperature
stress state
strain state
Opis:
W artykule podjęto próbę wstępnej oceny wpływu temperatury na stan naprężenia i odkształcenia w otoczeniu wyrobiska podziemnego na podstawie analizy zjawisk zachodzących w sąsiedztwie komory siłowni elektrowni "Porąbka-Żar". Wymienione zagadnienie ma szczególne znaczenie w odniesieniu do budowli wielkogabarytowej, z jaką mamy do czynienia w rozpatrywanym przypadku, dla której nawet niewielka zmiana temperatury może powodować duże wahania parametrów ważnych z punktu widzenia jej stateczności. Podstawą przeprowadzonej analizy były wyniki pomiarów realizowanych przez OBR BG "Budkop" w wymienionym wyrobisku. Przebiegi wybranych funkcji ciśnienia panującego w górotworze i jego rozwarstwień uzyskane z badań in situ powiązano zależnościami korelacyjnymi z temperaturą panującą w komorze. Zgodnie z przewidywaniami wynikającymi z teorii termosprężystości (w pracy zostały zawarte wyniki obliczeń przybliżonych), zaobserwowano istotny wpływ oddziaływania cieplnego na charakter zmian i wartości poszczególnych parametrów mierzonych.
In the paper preliminary estimation of the stress and strain state around the underground excavation under an influence of temperature is presented. Discussing problem is very important especially for the large chamber (e.g. chamber of the "Porąbka-Żar" power station is described) for which even small fluctuation of temperature can induce big changes of stresses, significant from a static point of view. The analysis presented in the paper is based on measurements that has been executed by Budokop in the excavation. The stress and delamination functions are got from measurements and temperature is taken in the chamber, are interconnected by correlation function. In accordance with expectations coming from the thermoelasticity theory (the paper includes results of approximate calculations), existence of the significant relationship between temperature field and parameters form measurements (i.e. stress and strain in the vicinity of the chamber) is found.
Źródło:
Górnictwo i Geoinżynieria; 2005, 29, 3/1; 189-197
1732-6702
Pojawia się w:
Górnictwo i Geoinżynieria
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Stress states caused in chamber of reinforced concrete grain silo by non-centric emptying on large eccentricities
Autorzy:
Prusiel, J. A.
Gierej, K.
Powiązania:
https://bibliotekanauki.pl/articles/178725.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
stress state
reinforced concrete structure
grain silo
non-centric emptying
Opis:
The article presents the analysis of complex stress states in the concrete structure of grain silos, caused by non-centric emptying. The authors present a combination of loads from the pressure of bulk solid on the silo chamber according to Eurocode 1, Part 4 [11], which should be taken into account when emptying on large eccentricities in action assessment class 3 (AAC3) silos. For the example of a cylindrical wheat silo with a height of 25 m and a diameter of 10 m, the researchers carried out an analysis regarding the impact of the size of the eccentric discharge outlet on the distributions of forces and bending moments in a reinforced concrete wall.
Źródło:
Studia Geotechnica et Mechanica; 2018, 40, 4; 282-291
0137-6365
2083-831X
Pojawia się w:
Studia Geotechnica et Mechanica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Steady and transient thermal state of turbine disc estimation for life time monitoring
Stałe i przejściowe oszacowanie stanu termicznego tarczy turbiny w celu monitorowania jej żywotności
Autorzy:
Martseniuk, Yevhen
Powiązania:
https://bibliotekanauki.pl/articles/36416847.pdf
Data publikacji:
2020
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Lotnictwa
Tematy:
lifetime
monitoring
thermal-stress state
model
żywotność
stan naprężenia termicznego
Opis:
In connection with increasing intensification of the working process in a gas turbine engine and increasing requirements for economy, the problem of defining and monitoring the main parts lifetime is becoming more vital. Modern algorithms of the monitoring systems are based on taking into account the levels of part temperature and total equivalent stress throughout the flight cycle. Thermal and stressstrain states of the critical zones of the main parts are determined on the basis of information received from the sensors installed in the engine gas path. Turbine disks are located in the internal cavities of the engine and are cooled by air from the compressor. However, in some designs, the disk cavity can be separated from the place of cooling air bleed by several stages of non-contact labyrinth seals, which will lead to some delay in changing the parameters of the cooling air flow when changing the engine operating mode. It has been observed that if this situation is not taken into account, it can lead to significant errors (more than 40%) in determining the lifetime for the peripheral zone of the disk. At the same time, this error is minimal for the hub and the middle zone of the disk, and the existing monitoring algorithms can be used.
W związku z coraz większą intensyfikacją procesu pracy w silniku turbiny gazowej i rosnącymi wymaganiami ekonomicznymi, coraz bardziej zaostrza się problem definiowania i monitorowania żywotności głównych części. Nowoczesne algorytmy systemów monitorowania opierają się na uwzględnianiu poziomów temperatury części i całkowitego równoważnego obciążenia w całym cyklu lotu. Stany termiczne i naprężeniowo-odkształceniowe stref krytycznych części głównych określane są na podstawie informacji otrzymywanych z czujników zainstalowanych w torze gazowym silnika. Tarcze turbinowe umieszczone są w wewnętrznych wnękach silnika i są chłodzone powietrzem ze sprężarki. Jednak w niektórych konstrukcjach wnęka tarczowa może być oddzielona od miejsca upustu powietrza chłodzącego kilkoma stopniami bezdotykowych uszczelnień labiryntowych, co spowoduje pewne opóźnienie zmiany parametrów przepływu powietrza chłodzącego przy zmianie trybu pracy silnika. Wykazano, że jeśli sytuacja ta nie będzie brana pod uwagę, może to prowadzić do znacznych błędów (ponad 40%) w określeniu okresu eksploatacji dla strefy peryferyjnej tarczy. Jednocześnie błąd ten jest minimalny dla koncentratora i strefy środkowej dysku, a istniejące algorytmy monitorujące mogą być stosowane.
Źródło:
Transactions on Aerospace Research; 2020, 3 (260); 21-29
0509-6669
2545-2835
Pojawia się w:
Transactions on Aerospace Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Friction heating and stress-strain state of ventilated disc brakes
Autorzy:
Holenko, Kostyantyn
Dykha, Oleksandr
Babak, Oleg
Posonskiy, Sergiy
Powiązania:
https://bibliotekanauki.pl/articles/2204250.pdf
Data publikacji:
2023
Wydawca:
Fundacja Centrum Badań Socjologicznych
Tematy:
brake discs
thermal load
stress-strain state
safety
stress
heat flow
Opis:
This paper describes the study of ventilated car disc brakes stress-strain conditions and friction under the pressure using the ANSYS environment. Such influencing factors are taken into account in the course of research as angular speed value, the pressure of the pads on the disk, the nature of the load application, convection, thermal expansion, etc. Computer modelling of the stress field and the transient thermal field in the area of contact between the pads and the disk is provided by the method of sequential thermostructural communication of the intermediate states of the brake model directly in the ANSYS Coupled Field Transient environment. Besides, the ANSYS calculations were also performed based on the primitive assembly model of two steel blocks (the discrepancy was less than 3%) to determine the identity of the theoretical knowledge about the heating of bodies as a result of the work to overcome frictional forces. Finally, a high level of calculation results convergence by analytical formulas and computer modelling was established. Since this approach justified itself, its principles were taken as a basis in the calculations of ventilated disc brakes of cars, which significantly facilitates their application, knowing the area of the active part of the disc (the rest of the boundary conditions are typical and correspond to the normal operating modes of the vehicle).
Źródło:
Journal of Sustainable Development of Transport and Logistics; 2023, 8, 1; 43--52
2520-2979
Pojawia się w:
Journal of Sustainable Development of Transport and Logistics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modeling of the stress-deformed state and cracking inreinforced concrete structures using ANSYS Mechanical
Autorzy:
Dorofeev, V. S.
Karpyuk, V. M.
Neutov, O. S.
Neutov, S. F.
Powiązania:
https://bibliotekanauki.pl/articles/950449.pdf
Data publikacji:
2014
Wydawca:
Uniwersytet Warmińsko-Mazurski w Olsztynie
Tematy:
concrete beam
stress-strain state
finite element modeling
ANSYS
Opis:
The article presents the results of reinforced concrete beams modeling under short-term loading with the use of the ANSYS Mechanical software. The obtained parameters were compared with the experimental ones. The comparison showed a satisfactory concordance of the parameters. In case of the discrepancies, the authors suggest that they are due to the idealization of material properties and structural model of the finite method. The paper is divided into the following chapters: Introduction, Literature Review, Research Significance, Element Types, Real Constants, Material Properties Modeling, Geometric Modeling, Loads and Boundary Conditions, Cracking and Failure and Conclusions. Each of the five conclusions in the last chapter offers a summary of the presented experimental research.
Źródło:
Technical Sciences / University of Warmia and Mazury in Olsztyn; 2014, 17(2); 105-121
1505-4675
2083-4527
Pojawia się w:
Technical Sciences / University of Warmia and Mazury in Olsztyn
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wpływ szerokości filara oporowego dla chodnika przyścianowego na stan naprężenia w jego otoczeniu
The influence of support pillar for the main gate on the state of stress
Autorzy:
Majcherczyk, T.
Niedbalski, Z.
Małkowski, P.
Powiązania:
https://bibliotekanauki.pl/articles/349869.pdf
Data publikacji:
2011
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
filary międzychodnikowe
chodniki przyścianowe
stan naprężenia
intergate pillars
gates
stress state
Opis:
W artykule przedstawiono analizę wpływu szerokości filara pozostawionego pomiędzy zrobami zawałowymi a chodnikiem przyścianowym wykonanym dla sąsiedniej ściany na zmianę stanu naprężenia i wytężenia. Dla zapewnienia funkcjonalności chodnika drążonego dla nowej ściany, przeanalizowano szerokości filara od 4 m do 10 m. Analizowany przypadek dotyczy konieczności określenia lokalizacji chodników przyścianowych dla zamykających ścian B-11 i B-11a w pokładzie 348. Warunki górniczo- geologiczne w opisywanym przypadku należy uznać za szczególnie trudne ze względu na duże nachylenie pokładu sięgające 240, znaczne zagrożenie metanowe oraz obustronne otoczenie ściany zrobami zawałowymi. Lokalizacja przedmiotowych wyrobisk uwzględnia warunki ekonomiczne i jednocześnie optymalną szerokość filara, która będzie zapewniać stateczność wyrobisk przyścianowych.
The paper presents the analysis of the influence of support pillar width left between a goaf and a gate drifted for the consecutive longwall on the state of stress and strain. The widths of pillar from 4 m to 10 m were analyzed to ensure the gate functionality for the subsequent longwall panel. The case concerns the necessity of defining main gate locations which close the panel for longwalls B-11 and B-11a in the seam 348. The mining and geological conditions on the spot were found as exceptionally hard due to bed inclinations up to 240, methane hazard and goafs on both sides of the longwall panel. The location of the analyzed workings takes into consideration both the economic conditions and the optimal pillar width, which additionally ensure gate stability.
Źródło:
Górnictwo i Geoinżynieria; 2011, 35, 2; 415-424
1732-6702
Pojawia się w:
Górnictwo i Geoinżynieria
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of an equivalent truss model for determining the stress state in multi-phase materials with cellular automata method
Autorzy:
Staszczyk, A.
Sawicki, J.
Powiązania:
https://bibliotekanauki.pl/articles/103191.pdf
Data publikacji:
2017
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
Cellular Automata
numerical methods
stress state
strength of materials
precipitation hardening
Opis:
The Cellular Automata represent a universal method of modelling and simulation. They enable the performance of calculations for even the most complex processes and phenomena. They are also used successfully in mechanical and material engineering. In this paper, the concept of application of the Cellular Automata method for simulating the behaviour of material under stress is presented. The proposed numerical algorithm created performs a number of calculations of local stress states in the structure of precipitation hardened material. The principle of its operation is based on the application of the equivalent truss model, which is often used in the optimisation and design of structures. In this paper, this model was used to simulate a system embodying a section of the material containing various phases with different mechanical properties.
Źródło:
Advances in Science and Technology. Research Journal; 2017, 11, 2; 51-57
2299-8624
Pojawia się w:
Advances in Science and Technology. Research Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the choice of thickness of the cement mantle in cemented hip arthroplasty
Autorzy:
Levadnyi, I.
Awrejcewicz, J.
Loskutov, A.
Szymanowska, O.
Powiązania:
https://bibliotekanauki.pl/articles/279791.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
total hip replacement
bone cement
femur
stress state
finite elements method
Opis:
Recommendations for the optimal thickness of the cement mantle in cemented hip arthroplasty are outlined based on the results obtained with the finite element method. The investigations show that distal femur cement thickness higher than 2 mm positively affects mechanical behaviour of the cement mantle and can be useful in reducing stress-strain levels in the distal part of the femur what leads to prevention of development of a stress-shielding effect. The results of the study can contribute to the success of long-term implants.
Źródło:
Journal of Theoretical and Applied Mechanics; 2017, 55, 4; 1235-1244
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental and Numerical Stress State Assesment in Refill Friction Stir Spot Welding Joints
Autorzy:
Gadalińska, Elżbieta
Kubit, Andrzej
Trzepieciński, Tomasz
Moneta, Grzegorz
Powiązania:
https://bibliotekanauki.pl/articles/2105194.pdf
Data publikacji:
2021
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Lotnictwa
Tematy:
RFSSW
X-ray diffraction
finite elements modelling
stress state
aluminium alloys
Opis:
Refill Friction Stir Spot Welding (RFSSW) is a technology used for joining solid materials that was developed in Germany in 2002 by GKSS-GmbH as a variant of the conventional friction stir spot welding (FSSW) [1]. In the RFSSW technology, the welding tool consists of a fixed outer part and rotating inner parts, which are called a pin and a sleeve. The tool for RFSSW is designed to plasticize the material of the parts to be joined by means of a rotary movement. The design of the tool allows independent vertical movement of both elements of the welding tool. This allows obtaining spot welds without creating holes that could weaken the structure. The main advantage of RFSSW is the potential for replacing the technologies that add weight to the structure or create discontinuities, such as joining with screws or rivets. Thus, RFSSW has great potential in the automotive, shipbuilding and aviation industries. Furthermore, the technology can be used to join different materials that could not be connected using other joining methods. The main objective of this work is to understand the physical and mechanical aspects of the RFSSW method - including the residual stress state inside the weld and around the joint. The results of the investigations can help to determine optimal parameters that could increase the strength and fatigue performance of the joint and to prove the significant advantage of RFSSW connections over other types of joints. The work assumes the correlation of two mutually complementary investigation methods: numerical analyses and experimental studies carried out with diffraction methods. The comparison between numerical and experimental results makes potentially possible the determination of degree of fatigue degradation of the material by observing the macroscopic stress state and the broadening of the diffraction peak width (FWHM), which is an indicator of the existence of micro-stress related to the dislocation density and grain size.
Źródło:
Fatigue of Aircraft Structures; 2021, 13; 54--71
2081-7738
2300-7591
Pojawia się w:
Fatigue of Aircraft Structures
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of increasing mining rate on longwall coal mining – Western Donbass case study
Autorzy:
Sdvyzhkova, O.
Patyńska, R.
Powiązania:
https://bibliotekanauki.pl/articles/178393.pdf
Data publikacji:
2016
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
rock
stress-strain state
mining rate
failure criterion
roof collapse
Opis:
This paper presents the problems associated with the rapid change of the rock stress-strain state in terms of increasing the rate of coal mining. Parameters of the roof collapse are determined depending on the rate of a longwall advancing under conditions of poor rocks. Statistical data are processed to obtain a general trend concerning the mining rate impact on the roof collapse. The statistical strength theory is applied to explain the increase in mined-out space and the size of hanging roof behind a coal face. Numerical simulation is carried out to determine a critical size of mined-out space that provokes a roof collapse. The area of yielded rocks is outlined using the criterion developed taking into account the rate of longwall advancing. A general regularity is obtained to determine the roof collapse parameters. The developed technics gives a possibility to predict the moment of general roof collapse at the initial stage of longwalling to prevent the negative effect of the rapid stress redistribution provoking joints propagation and intensive gas release. The estimation of the rock stress-strain state considering the rate of mining operations can be useful for tasks related to a new technology implementation. The statistical strength theory and failure criterion applied together provides adequate planning of mining activities and the assessment of natural hazards.
Źródło:
Studia Geotechnica et Mechanica; 2016, 38, 1; 91-98
0137-6365
2083-831X
Pojawia się w:
Studia Geotechnica et Mechanica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The influence of operating loads on the state of stress and strain in selected load-bearing elements of a tower-type headgear structure
Wpływ obciążeń eksploatacyjnych na stan naprężenia oraz przemieszczenia wybranych elementów nośnych konstrukcji basztowej wieży szybowej
Autorzy:
Wolny, S.
Powiązania:
https://bibliotekanauki.pl/articles/219470.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
basztowe wieże wyciągowe
stan naprężenia
obciążenia
tower-type headgear
stress state
loading
Opis:
The headgear structure allows the conveyance to be moved over the shaft top to the loading (unloading) point, at the same time it keeps in place the rope pulleys while tower-type headgear structures also accommodate the entire winder installations. The headgear is where the final stage of the hoisting installation is located and where the surface transport systems begin. These aspects strongly impact the actual shape of the tower, its height and in some cases determine the design of the entire winding gear. In order that all the headgear functions should be provided, it is required that the ultimate state conditions should be maintained throughout its entire service life. In order to assess the critical service conditions, the computation procedure should be applied based on design loads and fatigue endurance parameters. The computations of characteristic loads acting on the headgear structure use the developed model of the system based on the dynamic analysis carried out for a specific case: a hoisting installation operated in one of the underground collieries in Poland. The maximal and minimal loads acting on a Koepe pulley and those required for the system operation are determined accordingly. The laws of dynamics provide a background for finding the forces and moments of forces acting in the components of the driving system (including the electric motors and pulley blocks) for the specified loading of the Koepe pulley. Underlying the numerical FEM model of the tower-type headgear structure are the technical specifications of the analysed object and FEM calculations followed by endurance analysis to find the state of stress in structural elements of the headgear under the typical service conditions. The results help in assessing how the design of the hoisting installation should impact on safety features of load-bearing elements in the headgear structure.
Wieża szybowa jest konstrukcją umożliwiającą wyprowadzenie naczynia wydobywczego ponad zrąb szybu do miejsca wyładunku (bądź załadunku) i jednocześnie podtrzymuje koła linowe, a w przypadku wież basztowych, całą maszynę wyciągową. W wieży mieści się końcowy odcinek transportu pionowego i zaczyna transport powierzchniowy. Fakt ten w istotny sposób wpływa na kształt wieży, w tym na jej wysokości, a często decyduje o konstrukcyjnym rozwiązaniu całego urządzenia wyciągowego. W tym kontekście, poprawne spełnienie wszystkich funkcji wieży szybowej, będzie na etapie eksploatacji urządzenia, wymagać zapewnienia warunków stanu granicznego użytkowalności. Obliczenie stanu granicznego użytkowalności, wymagają stosowania obliczeniowych wartości obciążeń i obliczeniowych wartości wytrzymałości. W celu wyznaczenia charakterystycznych wartości obciążeń konstrukcji wieży szybowej, w oparciu o opracowany model układu, przeprowadzoną analizę dynamiczną, przykładowo dla urządzenia wydobywczego pracującego w jednej z polskich kopalń, wyznaczono maksymalne i minimalne wartości obciążenia konstrukcji koła pędnego, konieczne do realizacji procesu. Korzystając z zasad dynamiki, dla określonych wartości obciążenia koła pędnego, wyznaczono siły i momenty w elementach układu napędowego, w tym silników elektrycznych, kół kierujących. Bazując na dokumentacji technicznej analizowanego obiektu, opracowano model numeryczny MES konstrukcji nośnej wieży szybowej, a następnie wykonano analizę wytrzymałościową - stanu naprężenia w elementach konstrukcyjnych wieży szybowej - wywołanego normalną eksploatacją wyciągu. Wyniki przeprowadzonych analiz i obliczeń, pozwoliły na ocenę wpływu podstawowych parametrów wyciągu, na bezpieczeństwo eksploatacji elementów nośnych konstrukcji wieży szybowej.
Źródło:
Archives of Mining Sciences; 2012, 57, 3; 497-515
0860-7001
Pojawia się w:
Archives of Mining Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-25 z 123

Ta witryna wykorzystuje pliki cookies do przechowywania informacji na Twoim komputerze. Pliki cookies stosujemy w celu świadczenia usług na najwyższym poziomie, w tym w sposób dostosowany do indywidualnych potrzeb. Korzystanie z witryny bez zmiany ustawień dotyczących cookies oznacza, że będą one zamieszczane w Twoim komputerze. W każdym momencie możesz dokonać zmiany ustawień dotyczących cookies