Temat: numerical modelling - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Bird modelling for simulation of bird strikes
Autorzy:: Ćwiklak, J.
Powiązania:: https://bibliotekanauki.pl/articles/245094.pdf
Data publikacji:: 2015
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: bird strike
simulation
numerical modelling
Opis:: As proved in the conducted analyses, one of the factors, which, to a large degree, exerts a negative influence on flight safety, is a potential possibility of a collision of an aircraft with birds, in particular at an airfield or in its vicinity [12, 16]. Various parts of an aircraft are subjected to damage. It appears that damage to the engine as well as penetration of the windshield is extremely dangerous. The consequence of a bird falling into the engine can be engine shutting down [6, 21], whereas penetrating the canopy can cause a serious injury to the pilot, making him unable to continue piloting an aircraft. The analysis of the literature of the object of study [7] shows that the most damage of the windshield occurs in the category of aircraft and small helicopters, whose certification requirements were not specified in this case [1, 19]. It should be remembered that apart from the compulsory experimental strength tests, conducted in laboratory conditions in order to meet certification requirements, there exist various theoretical methods, which are realized based on proper mathematical modelling of the strike event [5, 10]. Therefore, due to lack of certification requirements for the category of normal aeroplanes and small helicopters and a high degree of damage, especially to the cockpit canopy, it seems justified to conduct simulation of the strike impact by means of proper software. In order to perform the modelling in question, it is necessary to select a proper bird model and a suitable simulation method, including appropriate software. Based on the available literature devoted to the subject, there are several methods of modelling a bird shape. Investigations exploit various geometrical figures in order to model the bird shape, the most common one being a cylinder, an ellipsoid and a cylinder with hexagonal endings [10]. The aim of this article is to analyse the selected methods in order to choose one of them for further research connected with the simulation of bird-strike events into a cockpit windshield of selected aircraft.
Źródło:: Journal of KONES; 2015, 22, 2; 25-32
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Isotropic damage in viscoplastic flow conditions, FEM applications with practical examples
Autorzy:: Kłosowski, P.
Pyrzowski, Ł.
Powiązania:: https://bibliotekanauki.pl/articles/243317.pdf
Data publikacji:: 2008
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: FEM
viscoplacticity
isotropic damage
constitutive modelling
numerical modelling
Opis:: The damage mechanics is a very important branch of solid mechanics. Although it is still developing, it has already been applied to many engineering problems. Among many various types of damage models, which are commonly used, the main subject of this paper is the isotropic continuous damage in viscoplastic flow conditions. This paper include Information about the viscoplastic type of constitutive modelling, the presentation of mechanical representation of damage by the scalar variable D, effective stress concept, equations of the chosen isotropic damage model, the Chaboche viscoplastic constitutive model including damage effects and the identification procedure of damage material parameters with practical example. The chosen constitutive model is easy to apply to the finite element analysis. Using the MSC.Marc system, which great advantage is possibility ofa user subroutine application, the geometry nonlinear finite element analysis of plate and shell structures including damage is possible. This paper includes description of the applied program and user subroutines applied: UVSCPL - viscoplastic modelling (the standard MSC.Marc system supports the Chaboche model, but not in the damage variant) and UACTIV - deactivation of finite elements. The last part of the paper includes the practical numerical example of a clamped bar of 0.3 m long and 0.1x0.01 m cross-section size. In calculations the four-node thin-shell, divided into five layers, elements were used. dynamic, geometrically nonlinear analysis using Newmark integration algorithm has been performed. As the results, screen shots of displacements with maps of damage parameter for the bar infour time moments are presented.
Źródło:: Journal of KONES; 2008, 15, 1; 127-136
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Numerical model of bullet - barrel system
Model numeryczny układu lufa - pocisk
Autorzy:: Łazowski, J.
Małachowski, J.
Niezgoda, T.
Powiązania:: https://bibliotekanauki.pl/articles/241651.pdf
Data publikacji:: 2007
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: lufa
pocisk
modelowanie numeryczne
barrel
bullet
numerical modelling
Opis:: Aktualnie, projektowanie uzbrojenia w dużej mierze opiera się na metodach analitycznych, które nie pozwalają na znaczną poprawę parametrów broni w zakresie odporności udarowej. Szczególnie istotna jest analiza dynamiki dla ruchu pocisku w lufie na stożku przejściowym i ustalenie optymalnych parametrów procesu. Na styku lufy i pocisku zachodzą bardzo złożone procesy termomechaniczne. Oddziaływanie to powoduje powstawanie na powierzchni styku ciał ciepła a w konsekwencji zmian właściwości mechanicznych. Dodatkowo charakter współpracy obu ciał obarczony jest często brakiem symetrii wynikającym między innymi z niedokładności wykonania elementów, nieodpowiednim osadzeniem pocisku w lufie oraz niejednorodnością materiałów. W skutek takiej złożoności zjawisk, której konsekwencją są np. zmienność współczynnika tarcia czy również drgania pocisku i lufy, ogólne analityczne wyznaczanie stanów naprężeń i stanów krytycznych w sposób ścisły jest niemożliwe. Jedyną skuteczną metodą może być w tym przypadku modelowanie numeryczne. W pracy przedstawiono próbę analizy stanu wytężenia powstającego podczas szybkozmiennych procesów w trakcie współpracy pocisku z lufą. Przedstawiono model numeryczny obiektów i zaprezentowano wyniki analizy w formie planów warstwicowych. Narzędziem zastosowanym do analizy był pakiet obliczeniowy LS-DYNA umożliwiający symulacje w zakresie nieliniowym z jawnym krokiem całkowania.
Currently the design process for armament equipment mostly employs very known and traditional analytical methods. But in many cases this kind of approach is not sufficient and effective, especially for gun parameters related with impact resistance. Very crucial for proper dynamic bullet movement in the barrel are geometric dimensions. In the contact areas between a bullet and a barrel appear some thermo-mechanical phenomena. Additionally, the cooperation process between these two components is encumbered because of the asymmetry caused by the inaccuracy of production process and the inhomogeneity of used materials. Finally, the mentioned reasons produce some unwanted effects like: bullet and barrel vibrations, problems with friction phenomena, etc. In such situations, the typical engineering approach in design process is unable to take into considerations all such local and very complex effects. Therefore, this paper presents is a trial of numerical methods application, which allow perform full analysis process of interaction between bullet and barrel. The models of these two bodies were developed using FE method. The numerical calculations were performed using LS-DYNA code. The main goal of the research was focused on contact problem. In the paper authors enclosed the initial results of the dynamic simulations.
Źródło:: Journal of KONES; 2007, 14, 1; 261-266
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Arch bridges under test loadings
Autorzy:: Chróścielewski, J.
Malinowski, M.
Miśkiewicz, E.
Powiązania:: https://bibliotekanauki.pl/articles/243342.pdf
Data publikacji:: 2008
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: bridge
FEM
test loads
numerical modelling
arch bridges
Opis:: According to the Polish bridge design code road bridges with spans over 20 m and all railway bridges, before they are given to public usage, all require the conduction of studies during a test loading. This paper is an illustration to the experience in arch bridge test loadings of the research team of Department of Structural Mechanics and Bridge Structures from the Gdansk University of Technology. It concerns the applied computational conceptions and researches on an example of three arch bridges, built between 2005 and 2007. The presented calculations results consists the analysis of spatial construction schemes made using the finite elements method (FEM) and its comparison to the field studies. The goal of the studies is to check the correctness of the construction 's work and of the design assumptions. Arch bridges with the longest spans, visualisation of the computational model, the displacement - deflection graphs of the arch bridge construction, generating the extreme span 's deflections, results of the calculations and field dynamic measurements of the some bridges, example of computation results and field dynamic measurements during the static tests are presented in the paper.
Źródło:: Journal of KONES; 2008, 15, 1; 29-38
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Flammable mixture formation and mixing rates of transient gaseous fuel jet with air in tumbling or swirling motion
Autorzy:: Gharib, N.,
Sobiesiak, A.
Powiązania:: https://bibliotekanauki.pl/articles/248093.pdf
Data publikacji:: 2008
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: mixing
axial swirl
barrel swirl (tumble)
numerical modelling
KIVA
Opis:: In this study the effects of angular momentum (barrel and axial swirl) on flammable mixture formation and mixing rate between chamber air and transient gaseous jets of hydrogen and methane were numerically investigated in several geometric configurations; in fixed volume cubic and cylindrical chambers, and in a variable volume cylindrical chamber with moving piston. The magnitude of the momentum, injection duration, and injection velocity are the main parameters whose effects were investigated. In the cylindrical chamber with mowing piston dissipation of a bulk air motion vortex, and the angular momentum decay during compression were also studied The numerical simulations were carried out with the use of KIVA3V code modified for gaseous injection with a standard k-e model for turbulence. It was found that hydrogen jet and air mixing under application of angular momentum lead to fast formation of flammable mixture, with the mixing rates several times larger than those for methane jet. Also dynamics of the hydrogen mixing as illustrated by the mixing rate curves is markedly different from those for methane with the same magnitude of angular momentum. The mixing rate curves for hydrogen feature one strong local maximum at time which is half or less of the hydrogen jet injection duration time. Mixing of methane jet with air at all conditions resembles that of hydrogen jet mixing with air at zero or lower levels of angular momentum.
Źródło:: Journal of KONES; 2008, 15, 3; 147-153
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Experimental and numerical investigation of energy absorption elastomer panel with honeycomb structure
Autorzy:: Bogusz, P.
Popławski, A.
Morka, A.
Stankiewicz, M.
Sławiński, G.
Powiązania:: https://bibliotekanauki.pl/articles/246847.pdf
Data publikacji:: 2015
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: energy absorption structure
blast shock wave
numerical modelling
elastomer
validation
Opis:: The paper presents a prototype design of elastomer energy absorbing panel made in a shape of honeycomb structure. The proposed panel was installed in a protected plate and tested on a specially designed test stand, where a shock wave from a small explosive charge was applied. The elastomer honeycomb structure was compared with a version of the panel made of solid elastomer materials, the same as used in the honeycomb structure and also with a protected plate without any panels. During the research, acceleration in the middle part of each investigated protected plate was recorded. The protected plates were scanned after the tests in order to measure their maximum deformation. Acceleration graphs and maximum deflections of all three considered structures were compared. The obtained results were used to validate numerical models of the designed structures and the test stand. A discreet model of the test stand and models of elastomer panels were developed with HyperMesh FEM software using shell and solid elements. The materials were described using a tabulated Johnson-Cook model and constitutive model for the rubber parts; all available in the material library of Ls-Dyna software. The blast loading was simulated using the CONWEP method. This model generates a boundary condition, based on the experimental data and TNT equivalent mass, which substitutes the wave propagation with a pressure. Finally, the experimental results of acceleration and deformation of the plates were compared with the corresponding results of the numerical analyses carried out using finite element method. The numerical models can be utilised in the future research as a virtual range stand. The developed elastomer honeycomb structure can be modified to meet various requirements of ballistic protection levels, by applying elastomer of different stiffness or optimizing shape and dimensions of the honeycomb structure.
Źródło:: Journal of KONES; 2015, 22, 4; 29-36
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Numerical simulation of the beam made of magnetorheological elastomer bending in the magnetic field
Autorzy:: Miedzińska, D.
Sławiński, G.
Boczkowska, A.
Powiązania:: https://bibliotekanauki.pl/articles/245981.pdf
Data publikacji:: 2010
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: magnetorheological elastomer
smart materials
numerical modelling
magnetic field influence
Opis:: Magnetorheological elastomers (MREs) belong to the group of so-called smart materials, which respond to an external stimulus by changing their viscoelastic properties. Magnetorheological (MR) material can be fluid, gel or solid like material, such as elastomer. The mechanical properties of the MR materials change when subjected to an external magnetic field. The MREs are interesting candidates for the active stiffness and vibration control of structural systems. In the paper the verification process of the applied FE modelling method is presented. The verification is based on the three point bending experiment. The results of that experiment were used to evaluation of the correction on numerical model and analysis. The model was based on the assumption that MRE behaves like an orthotropic material with the material properties o f MRE on the direction along the iron chains - and of a pure elastomer - on the other directions. Such an assumption can be made for the small deformations of a sample, what took place in the considered experiment. The FE modelling method was considered to be correct. On the base of the verified method a FE element model of the MRE beam bending was developed. Such MRE beams are used as "smart" switches that react under the changeable magnetic field.
Źródło:: Journal of KONES; 2010, 17, 1; 261-265
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Numerical modelling and validation of 12.7 MM FSP impact into ALFC shield - ARMOX 500T steel plate system
Autorzy:: Klasztorny, M.
Świerczewski, M.
Powiązania:: https://bibliotekanauki.pl/articles/242187.pdf
Data publikacji:: 2012
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: light armoured vehicles
passive protection
IED
FSP
numerical modelling
simulation
validation
Opis:: The study develops a methodology for numerical modelling and simulation of a 12.7 mm 13.4 g FSP fragment impact into the ALFC shield – ARMOX 500T steel plate system. The ALFC shield is composed of the ALF energyabsorbing subsystem and a 10 mm-thick 99,7% Al2O3 alumina ceramic layer. The ALF subsystem is designed to absorb blast wave impact energy induced by explosive materials up to 10 kg TNT. The ceramic layer is designed to stop fragments from IED explosion. The 5 mm-thick Armox 500T steel plate constitutes the body bottom segment of a light armoured vehicle. The ALF subsystem has the following layered structure: Al2024 aluminium alloy plate, SCACS hybrid laminate plate, ALPORAS aluminium foam, SCACS hybrid laminate plate. The layers are joined with Soudaseal 2K chemoset glue. SCACS hybrid laminate contains the following components: VE 11-M modified vinylester resin (matrix), SWR800 S-glass plain weave fabric, Tenax HTA40 6K carbon plain weave fabric, Kevlar 49 T 968 aramid plain weave fabric. The total thickness of the ALFC shield amounts to 90 mm. Proof ground tests of a 12.7 mm 13.4 g FSP fragment impact into the ALFC shield - ARMOX 500T steel plate system have been performed at impact velocity 715 m/s and used for experimental validation of numerical modelling and simulation. In the numerical modelling, the aluminium alloy plate and Armox 500T steel plate are working in the elasto-plastic range according to Johnson-Cook model. The 99.7% Al2O3 alumina ceramic is working in elasto-short range according to JH-2 Johnson-Holmquist model. The simulations correspond to large displacements, large deformations and potential contact among all the components of the system. In FE mesh, the 8-node 24 DOF hexahedral finite elements with single integration point have been used. Failure criteria governing ad-hoc erosion of finite elements have been applied. The FEM modelling, simulation and postprocessing have been carried out using Catia, HyperMesh, LS-DYNA and LS-PrePost systems. The simulation results in the form of displacement/penetration contours and the FSP final deformation have been compared with the experimental results.
Źródło:: Journal of KONES; 2012, 19, 4; 291-299
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Preliminary concept of numerical modelling of combustion process for gunpowder using LS-DYNA code
Wstępna koncepcja numerycznego modelowania procesu spalania ładunku miotającego w systemie LS-DYNA
Autorzy:: Łazowski, J.
Małachowski, J.
Niezgoda, T.
Powiązania:: https://bibliotekanauki.pl/articles/241653.pdf
Data publikacji:: 2007
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: lufa
pocisk
modelowanie numeryczne
balistyka wewnętrzna
spalanie
barrel
bullet
numerical modelling
internal ballistic
gunpowder burning
Opis:: In this paper the preliminary concept of numerical modelling of combustion process for gunpowder is presented. Such new computational methods like finite element analysis gave us opportunity to simulate such energetic and high-frequency process like pressure wave generation caused by chemical reaction. The main product of this process is a blast wave, which interacts at the first stage with surrounding (bullet and shell) and finally impel a bullet movement. In the considered case, the detonation product from gunpowder burning couple "produced" gas in Eulerian domain with the barrel-bullet system described in Lagrangian domain. In the performed analysis, the authors noticed some unwanted effects like asymmetry, which is probably related with the finite element mesh and computational errors. In the next conducting investigations some optimisation procedures related with a bullet movement in a barrel will be employed. The successful solution of such complicated problem like a proper simulation of the internal ballistic phenomena with taking into account all dynamic effects can significantly improve the problem of shooting accuracy. The initial calculations were performed using LS-Dyna code. At this stage the presented results have a qualitative character.
W pracy omówiono koncepcję symulacji komputerowej spalania materiału wybuchowego miotającego w układzie lufa- nabój. Takie nowoczesne sposoby obliczeniowe, oparte na metodzie elementów skończonych mogą dostarczyć możliwości symulacji szybkozmiennych procesów energetycznych wynikających ze zamiany energii chemicznej prochu na ciśnienie gazów prochowych i w konsekwencji w energię kinetyczną pocisku. Okazuje się, że zamodelowanie wytwarzania produktów spalania materiału miotającego jest zadaniem trudnym. W takich ekstremalnych warunkach charakter współpracy obu ciał może być obarczony np. brakiem symetrii wynikającym między innymi z asymetrycznego rozkładu ciśnienia produktów spalania materiałów miotających. W przypadku modelu dyskretnego koncepcja ta może zostać wykorzystana do rozwiązania problemu głównego balistyki wewnętrznej i optymalizacji konstrukcji układu lufa - nabój oraz symulacji właściwości dynamicznych rozpatrywanych obiektów w różnych fazach współpracy. Poniżej przedstawiono klasyczne sformowanie modelu dla broni lufowej oparte równań matematycznych i sposób zaimplementowania w modelu dyskretnym. Rozważania zilustrowano przykładowymi wynikami. Pracę realizowano przy wykorzystaniu licencjonowanego pakietu obliczeniowego LS-Dyna. Przedstawione wstępne wyniki mają charakter jakościowy.
Źródło:: Journal of KONES; 2007, 14, 1; 255-260
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Dynamics analysis of the main landing gear in 3D model
Analiza dynamiczna podwozia głównego w modelu 3D
Autorzy:: Krasoń, W.
Małachowski, J.
Powiązania:: https://bibliotekanauki.pl/articles/247885.pdf
Data publikacji:: 2007
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: podwozie samolotowe
modelowanie numeryczne
zrzutowy test lądowania
MES (metoda elementów skończonych)
aircraft landing gear
numerical modelling
touchdown drop test
FEM
Opis:: Właściwie dobrane charakterystyki podwozia pozwalają minimalizować obciążenia występujące w podzespołach układu podwozia podczas jego pracy w momencie przyziemienia. W związku z tym wykonuje się analizy dynamiczne podwozi, aby przewidzieć ich zachowanie się w warunkach dla nich niebezpiecznych. Przeprowadzenie tego typu badań z wykorzystaniem metod numerycznych jest znacznie łatwiejsze i tańsze od prób stanowiskowych. W pracy omawiana jest metodyka modelowania podwozia głównego i procedury doboru parametrów opisujących rzeczywistą strukturę badanego układu. W celu określenia właściwości materiałowych elementów składowych układu podwozia definiowane są sprężyste i nieliniowe charakterystyki materiałowe. W modelu numerycznym MES uwzględniono następujące zagadnienia: kontakt pomiędzy współpracującymi częściami układu, zjawisko pochłaniania energii w amortyzatorze gazowo-cieczowym zastosowanym w podwoziu, oddziaływanie gruntu na odkształcalną oponę podczas przyziemienia. Wybrane wyniki analizy numerycznej odpowiadające przypadkowi maksymalnych obciążeń podwozia podczas przyziemienia na 3 punkty z maksymalną dopuszczalną prędkością pionową będą omawiane wraz z wynikami testów stanowiskowych. Prezentowana w pracy analiza jest pierwszą częścią badań numerycznych trwałości podwozia lotniczego.
Properly adjusted characteristics enable minimisation of loads that occur in the landing-gear components at the moment of touchdown. Therefore, dynamic analyses of the landing gear are conducted to provide capabilities to forecast their behaviour under hazardous conditions. This kind of investigation with numerical methods applied is much easier and less expensive than stand tests. However, the development of the landing gear FEM models is necessary. Methodology of the main landing gear numerical models developing and procedures of parameters selection for the real structure features representation is discussed in the paper. The nonlinear physical material properties were precisely defined. To describe material properties of all mechanical components of the landing gear, a materials chart describing parameters for the elastic range was used. In FEM model the following matters were taken into consideration: contact problems between collaborating elements, the phenomena of energy absorption by gas-liquid damper placed in the landing gear and the response of the landing gear during touchdown of a flexible wheel with the ground. Chosen results of the numerical analysis for the maximum load of the gear considered, corresponding to an aircraft's 3-point landing at maximum decline speed allowed have been compared to experimental research's results. The analysis presented in this paper is the first part of wider considerations concerning numerical assessment of landing gear life.
Źródło:: Journal of KONES; 2007, 14, 3; 305-310
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 11.

Tytuł:: A peculiarity of determining a static carrying capacity for the one-row ball slewing bearing loaded the large radial force
Autorzy:: Śpiewak, S.
Powiązania:: https://bibliotekanauki.pl/articles/246680.pdf
Data publikacji:: 2016
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: slewing bearing
one row ball slewing bearing
radial force
axial force
tilting moment
curve of the static carrying capacity
numerical modelling
Opis:: Slewing bearings are applied commonly in the following devices inter alia: harbour cranes, traveling cranes, radar stations, machinery underground and an opencast mining, armaments industry, building machines, medical analysis devices, rotary kilns, manufacturing systems, a power engineering. A static limiting load curve of the slewing bearings describes ranges of the allowable loads, which the bearing can be safely carried for assumption by a manufacturer durability. The static carrying capacity of a slewing bearing describe the relationship between a tilting moment M and an axial force Fa for assumed a value of a radial force Fr. The article concerns problems related to catalo selection of rolling bearings which are loaded the large radial forces which may by differently directed in relation to a tilting moment's vector. Manufactures of the slewing bearings mostly does not present in product catalogs of a static limiting load curve, which have taken into account an action the radial forces. According to an INA company, the radial forces are reduced to determining an equivalent tilting moment and an equivalent axial force. In this work, the static limiting load curves have been determined based on the FEM models, the equations of contact mechanics for the ball and the bearing raceway. The models were performed by use the ADINA system. Juxtaposition of results obtained on a basis of method's INA company and own model have been presented in form the static limiting load curves. The object of the analysis was the one row ball slewing bearing, domestic production, which is used in excavator type F250H.
Źródło:: Journal of KONES; 2016, 23, 3; 533-540
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 12.

Tytuł:: Comparison of the temperature distribution in the dry and wet cylinder sleeve in unsteady state
Autorzy:: Gustof, P.
Jędrusik, D.
Powiązania:: https://bibliotekanauki.pl/articles/243978.pdf
Data publikacji:: 2010
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: numerical techniques
analysis and modelling of heat loads
cylinder sleeve
FEM
Opis:: This paper presents the modelling of the heat loads in the dry and wet cylinder sleeve in unsteady state. Next compared the results obtained temperature distribution on the individual surfaces of the dry and wet cylinder from the moment of starting the turbocharged Diesel engine to the moment when the distribution of the temperature changed in a small range. Modelling was conducted based on the boundary conditions III kind as a function of time, which describes the convective heat transfer coefficient and the temperature of the surrounding surfaces of cylinder sleeve, appointed on the basis of the bizonal model. The thesis used thefinite elements method (FEM). The calculations show that topparts of the cylinder sleeve near of the mount flange heat up thefastest however the temperature in the bottom parts below the 3rd ring in the piston is the lowest. Higher temperature of the dry cylinder sleeve in relation to the wet is caused by the fact that different convective heat transfer coefficients on the side of the liquid coolant were assumed. The highest difference of average temperature occurs in the initial phase of heating up of the dry and wet cylinder sleeve between 5 and 15 second. In the result of carried out calculations it was stated that the cylinder sleeve fastest heats up during first 20 second of the engine work then the temperature starts to stabilize and in 40 second it changes in a small range.
Źródło:: Journal of KONES; 2010, 17, 3; 119-125
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 13.

Tytuł:: The modeling of the heat loads in the exhaust valve from and without regard of the carbon deposit
Autorzy:: Jędrusik, D.
Gustof, P.
Powiązania:: https://bibliotekanauki.pl/articles/243988.pdf
Data publikacji:: 2010
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: numerical techniques
analysis and modelling of heat loads
valve
carbon deposit
FEM
Opis:: This paper presents the modelling of the heat loads in the exhaust valve from and without regard of carbon deposit in initial phase of work of the turbocharged Diesel engine by using the two-zone combustion model, finite elements method (FES) and program Cosmos/M. In order to illustrate the problem the valve face is divided into two equal areas, then it was assumed that one of them is covered with a thin layer of carbon deposit. Modelling was conducted based on the boundary conditions III kind as a function of time, which describes the convective heat transfer coefficient and the temperature of the surrounding surfaces of valve. As a result of the calculations was compared obtained temperature distribution on the surfaces of the valve - with and without carbon deposit. The study also performed an analysis of the stress distribution that arises in the valve by the presence of the carbon deposit on the surface of the face valve. The analysis showed that the face valve heats up unevenly, more slowly on the side of the carbon deposit. Moreover small increase of the temperature causes the increase of the stress values. Maximum values of stresses do not appear in a valve face under a layer of carbon deposit but on the line distributing the surface covered with carbon deposit and without carbon deposit, near the valve face. These stresses cause the growth of microcracks in the area of the valve face, which finally give occasion to the defect of material, the damage of the valve and engine failure
Źródło:: Journal of KONES; 2010, 17, 3; 173-179
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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