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Tytuł:
Analysis of selected contact algorithms types in terms of their parameters selection
Autorzy:
Panowicz, R.
Powiązania:
https://bibliotekanauki.pl/articles/245114.pdf
Data publikacji:
2013
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
finite element method
contact
penalty method
Opis:
The analysis of many engineering problems involves not only deformation of the considered system, but occurrence of the interaction between the individual separate elements of the system as well. The occurrence of friction is the most common phenomenon occurring during this interaction. In the case of intense friction, the heat released in this process is also important. In computer methods of mechanics, the process of interaction between bodies is carried out using special algorithms. The most frequently applied are: the penalty method, the barrier method, direct elimination of constraints, the Lagrange multiplier method, the perturbed Lagrangian method, the augmented Lagrangian method, Nitsche method. Owing to its easy implementation process, an approach based on a penalty function is often applied. In this approach, the contact between the bodies can be identified with the presence of the spring between the elements of the bodies in the contact. The stiffness of the spring depends on: material bulk modulus, face area, volume or shell diagonal and a numerically selected scale factor. The article will present the results of analyses that will allow fast and easy selection of its value. In the analyses there were presented the results considering the basic types of contacts: node to surface, surface to surface and surface to surface mortar.
Źródło:
Journal of KONES; 2013, 20, 1; 263-268
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of magnetic field effect on ferromagnetic spheres embedded in elastomer pattern
Badanie wpływu pola magnetycznego na ferromagnetyczne kule w osnowie elastomerowej
Autorzy:
Boczkowska, A.
Czechowski, L.
Jaroniek, M.
Niezgoda, T.
Powiązania:
https://bibliotekanauki.pl/articles/280005.pdf
Data publikacji:
2010
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
magnetorheological elastomers
finite element method
photoelastic method
Opis:
The results of modelling of the magnetorheological elastomers (MREs) microstructure using Finite Elements Method (FEM) are shown. MREs are solids analogous to magnetorheological fluids consisting of carbonyl-iron particles and a soft elastomer matrix. Fabrication of MREs is performed in an external constant magnetic field. Due to the presence of this field, the ferromagnetic particles tend to arrange themselves into elongated chains according to the magnetic field lines. FEM analysis of the MREs microstructure takes into account two cases: magnetic power and elastic vectors as well as their interactions between the components of the composite. The paper describes spatial ordering of the particles based on their interactions with the magnetic field. Two phenomena were taken into account: the force of a magnetic field and the local magnetic dipoles. Both fields have been modelled for a circular conductor with electrical current.
W pracy przedstawiono wyniki modelowania mikrostruktury magnetoreologicznych elastomerów (MRE) z wykorzystaniem metody elementów skończonych (MES). MRE są odpowiednikami w stanie stałym cieczy magnetoreologicznych, złożonymi z cząstek żelaza karbonylkowego i miękkiej osnowy elastomerowej.Wytwarzanie MRE prowadzone jest w stałym polu magnetycznym. Pod wpływem pola cząstki ferromagnetyczne układają się w łańcuchy wzdłuż linii pola magnetycznego, tworząc strukturę kolumnową. W analizie MES mikrostruktury MRE rozpatrzono siły magnetyczne i sprężystości oraz ich wzajemne oddziaływania pomiędzy składnikami kompozytu. Przedstawiono przestrzenne rozmieszczenie cząstek w oparciu o ich oddziaływania w polu magnetycznym. W rozważaniach wzięto pod uwagę rozkład pola magnetycznego i momenty dipolowe cząstek. W obu przypadkach pole było zamodelowane dla kołowego przewodnika prądu elektrycznego.
Źródło:
Journal of Theoretical and Applied Mechanics; 2010, 48, 3; 659-676
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of the influence of the finite elements mesh density on the determined shaped charge jet parameters
Autorzy:
Panowicz, R.
Konarzewski, M.
Borkowski, J.
Milewski, E.
Powiązania:
https://bibliotekanauki.pl/articles/244994.pdf
Data publikacji:
2015
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
charge jet
finite element method
Euler method
Opis:
Article presents results of numerical analyses of the finite elements mesh density influence on the shaped charge jet stream formation process and its selected parameters. Authors considered classical shaped charge, which consists of the plastic explosive material, copper liner and aluminium case. To properly described, material properties of the liner and case of the shaped charge, the Johnson-Cook material model was used. Detonation process was described using burn model approach. Behaviour of the detonation process products was described by commonly used John-Wilkins-Lee equation of state. Due to the nature of the presented phenomenon, in which we are dealing with large strains and strain rates, for its modelling authors utilized Euler description, implemented in the LS-Dyna software. In these method material flows by the finite elements and mesh is not deformed. Such approach allows for modelling phenomena where large and very large deformations occur. Unfortunately, it can result in a destabilizing of the systems energy balance. In order to minimize dissipation processes, in calculations was used second order scheme because of the spatial variables and time. Analyses were performed in axially symmetric setup, which was possible due to the symmetry of the analysed system. Influence of the finite elements size on the process of jet stream formation and its selected parameters was analysed.
Źródło:
Journal of KONES; 2015, 22, 3; 329-335
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The stability of a steel welded girder with bending and shear forces included
Autorzy:
Sygulski, R.
Guminiak, M.
Polus, Ł.
Powiązania:
https://bibliotekanauki.pl/articles/387654.pdf
Data publikacji:
2017
Wydawca:
Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Tematy:
buckling analysis
finite element method
boundary element method
Opis:
The stability of the element of a steel welded girder subjected to bending and shear forces is considered. The considered element is a rectangular plate supported on boundary. The type of a plate boundary conditions depend on the types (thickness) of the stiffeners. Considered plate is loaded by in-plane forces causing bending and shear effects. The Finite Element Method was applied to carry out the analysis. Additionally the Boundary Element Method in terms of boundary-domain integral equation was applied to evaluate the critical shear loading.
Źródło:
Acta Mechanica et Automatica; 2017, 11, 1; 14-19
1898-4088
2300-5319
Pojawia się w:
Acta Mechanica et Automatica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Identification of the Heat Transfer Coefficient at the Charge Surface Heated on the Chamber Furnace
Autorzy:
Gołdasz, A.
Malinowski, Z.
Powiązania:
https://bibliotekanauki.pl/articles/356595.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
heat transfer coefficient
inverse method
finite element method
Opis:
The inverse method was applied to determine the heat flux reaching the charge surface. The inverse solution was based upon finding the minimum of the error norm between the measured and calculated temperatures. The charge temperature field was calculated with the finite element method by solving the heat transfer equation for a square charge made of 15HM steel heated on all its surfaces. On the basis of the mean value of heat flux, the value of the heat transfer coefficient at each surface was determined depending on the surface temperature of the material heated.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2A; 509-513
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
FEM-BEM coupling in the membrane structure-air interaction problem
Połączenie MES i MEB w zagadnieniach interakcji powłok membranowych i powietrza
Autorzy:
Sygulski, R.
Powiązania:
https://bibliotekanauki.pl/articles/281304.pdf
Data publikacji:
1998
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
finite element method
boundary element method
membrane structure
Opis:
This paper deals with the interaction problems between the lightweight membrane structure and surrounding air. The coupling of FEM and BEM is described and applied to analysis of aerodynamics of membrane structures. Three methods of FEM-BEM coupling are presented.
Praca dotyczy problemów interakcji lekkich przekryć membranowych i otaczającego powietrza. Omawia się połączenie metody elementów skończonych (MES) i metody elementów brzegowych (MEB) do analizy zagadnień aerodynamiki powłok membranowych. Przedstawiono trzy metody połączenia MES i MEB.
Źródło:
Journal of Theoretical and Applied Mechanics; 1998, 2; 513-520
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Selected aspects of modelling a phenomena occurring with very large strain rates on the example of the shaped charge jet stream forming process and explosive formed projectiles
Autorzy:
Panowicz, R.
Konarzewski, M.
Borkowski, J.
Milewski, E.
Powiązania:
https://bibliotekanauki.pl/articles/245630.pdf
Data publikacji:
2015
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
charge jet
EFP
finite element method
Euler method
Opis:
During the process of the shaped charge jet stream formation and creation of the explosive formed projectiles, we have to deal with strain rates reaching level of 107 1/s and strains larger than in other dynamic phenomena. Therefore, the correct numerical analyses of such problems are especially demanding, both in terms of preparation of the numerical model and time needed for obtaining the solution. For their execution, both meshfree and Euler description based computational methods are used. Due to very large deformations and associated with them numerical analyses errors, computational methods based on the Lagrange description are not used. Description of the materials behaviour has to take into account influence of the strain rate in wide range of parameters. In most cases, it is realized by using in computational analyses Johnson-Cook or Steiberg-Green constitutive models. These models provide an accurate description of the material parameters not only in the wide range of strain rates, but also in large scope of strains and temperatures. Article presents results of the numerical analyses concerning the influence of selected numerical and geometric parameters of the system on the process of shaped charge jet stream formation and creation of explosive formed projectile.
Źródło:
Journal of KONES; 2015, 22, 3; 187-192
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Heat Flux Identification at the Charge Surface During Heating in Chamber Furnace
Autorzy:
Gołdasz, A.
Malinowski, Z.
Powiązania:
https://bibliotekanauki.pl/articles/351346.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
heat flux
inverse method
finite element method
chamber furnace
Opis:
In this study, a method of determining the heat flux, which reaches the surface of a charge, has been presented with the use of an inverse analysis. The research on the heating process of a square 15HM steel charge was conducted in a natural gas-fired laboratory furnace. The inverse solution was based on the search of the minimum standard error between the measured and the calculated temperatures. The temperature of the charge has been calculated by the finite element method, solving the heat conduction equation for a square charge heated on all the surfaces. As a result, the mean value of the heat flux on each of the heated surfaces of the charge was estimated.
Źródło:
Archives of Metallurgy and Materials; 2016, 61, 4; 2021-2026
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Coupled Smoothed Finite Element-Boundary Element Method for Structural-Acoustic Analysis of Shell
Autorzy:
Tian, W.
Yao, L.
Li, L.
Powiązania:
https://bibliotekanauki.pl/articles/177260.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
SFEM
smoothed finite element method
FEM
finite element method
BEM
boundary element method
structural-acoustic analysis
Opis:
Nowadays, the finite element method (FEM) – boundary element method (BEM) is used to predict the performance of structural-acoustic problem, i.e. the frequency response analysis, modal analysis. The accuracy of conventional FEM/BEM for structural-acoustic problems strongly depends on the size of the mesh, element quality, etc. As element size gets greater and distortion gets severer, the deviation of high frequency problem is also clear. In order to improve the accuracy of structural-acoustic problem, a smoothed finite-element/boundary-element coupling procedure (SFEM/BEM) is extended to analyze the structural-acoustic problem consisting of a shell structure interacting with the cavity in this paper, in which the SFEM and boundary element method (BEM) models are used to simulate the structure and the fluid, respectively. The governing equations of the structural-acoustic problems are established by coupling the SFEM for the structure and the BEM for the fluid. The solutions of SFEM are often found to be much more accurate than those of the FEM model. Based on its attractive features, it was decided in the present work to extend SFEM further for use in structural-acoustic analysis by coupling it with BEM, the present SFEM/BEM is implemented to predict the vehicle structure-acoustic frequency response analysis, and two numerical experiments results show that the present method can provide more accurate results compared with the standard FEM/BEM using the same mesh. It indicates that the present SFEM/BEM can be widely applied to solving many engineering noise, vibration and harshness (NVH) problems with more accurate solutions.
Źródło:
Archives of Acoustics; 2017, 42, 1; 49-59
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
2D Structural Acoustic Analysis Using the FEM/FMBEM with Different Coupled Element Types
Autorzy:
Chen, L.
Zhao, W.
Liu, C.
Chen, H.
Powiązania:
https://bibliotekanauki.pl/articles/176330.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
boundary element method
finite element method
discontinuous boundary elements
acoustic fluid-structure interaction
fast multipole method
Opis:
A FEM-BEM coupling approach is used for acoustic fluid-structure interaction analysis. The FEM is used to model the structure and the BEM is used to model the exterior acoustic domain. The aim of this work is to improve the computational efficiency and accuracy of the conventional FEM-BEM coupling approach. The fast multipole method (FMM) is applied to accelerating the matrix-vector products in BEM. The Burton-Miller formulation is used to overcome the fictitious eigen-frequency problem when using a single Helmholtz boundary integral equation for exterior acoustic problems. The continuous higher order boundary elements and discontinuous higher order boundary elements for 2D problem are developed in this work to achieve higher accuracy in the coupling analysis. The performance for coupled element types is compared via a simple example with analytical solution, and the optimal element type is obtained. Numerical examples are presented to show the relative errors of different coupled element types.
Źródło:
Archives of Acoustics; 2017, 42, 1; 37-48
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modelling of silo discharge and filling problems by the material point method
Autorzy:
Więckowski, Z.
Powiązania:
https://bibliotekanauki.pl/articles/1955763.pdf
Data publikacji:
2003
Wydawca:
Politechnika Gdańska
Tematy:
granular flow
plasticity
viscoplasticity
finite element method
material point method
Opis:
The problems of flow of a granular material is the processes of silo discharge and filling are considered. Dynamic, two-dimensional problems are analyzed, both the plane and axisymmetric ones. The material point method is applied as an analytical tool, a variant of the finite element method capable of solving pertinent equations of motion on an arbitrary computational element mesh and tracing state variables at material points chosen independently of the mesh. The mechanical behaviour of a granular material is described with non-associative elastic-perfectly plastic and elastic-viscoplastic material models with the Drucker-Prager yield condition. The influence of friction between the flowing granular body and silo walls is taken into account. The material point method enables one to analyze silos of arbitrary shapes, including silos with inserts controlling the flow of the stored material. The mass and funnel types of flows are analyzed.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2003, 7, 4; 701-721
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical simulation of energy absorption in polyurethane foams under impact
Autorzy:
Jankowski, M.
Czechowski, L.
Kotełko, M.
Powiązania:
https://bibliotekanauki.pl/articles/241823.pdf
Data publikacji:
2012
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
polyurethane foams
energy absorption
lump mass method
finite element method
Opis:
Selection of proper mechanical characteristics of the padding material of the head rest, namely polyurethane foam, is particularly important in the design process of the vehicle seat head restraint. In the paper the code of numerical simulation of flexible polyurethane foam absorber response against impact of a rigid body (passenger's head) is presented. The code is based on the lump mass method. Basics of the numerical algorithm based on this method are presented. Material constitutive model of flexible polyurethane foam (FPF) derived on the basis of former experimental tests and used in the algorithm is described. Comparative results of numerical simulations together with results of experiments carried out on drop hammer rig with flat impact or are shown. The results are presented on diagrams of deceleration versus time. Also comparative Finite Element simulations are carried out. The FE simulation was performed using the implicit analysis, taking into account the multi-linear, hyper-elastic material model and large strain (non-linear geometric relations). The influence of damping coefficient on the deceleration characteristics was investigated. Some final conclusions concerning the applicability of the numerical code based on the lump mass method, as well as its advantages in comparison with the FE software are derived.
Źródło:
Journal of KONES; 2012, 19, 4; 245-252
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New electrical tomographic method to determine dampness in historical buildings
Autorzy:
Rymarczyk, T.
Adamkiewicz, P.
Duda, K.
Szumowski, J.
Sikora, J.
Powiązania:
https://bibliotekanauki.pl/articles/141049.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
electrical impedance tomography
inverse problem
finite element method
level set method
Opis:
This paper presents a new, nondestructive method of testing brick wall dampness in wall structures. The setup was used to determine the moisture in a specially built laboratory model. Topological methods and the gradient technique are used to optimize the approach. A forward model of a wall was constructed to solve the inverse problem resulting in moisture buildup inside the wall.
Źródło:
Archives of Electrical Engineering; 2016, 65, 2; 273-283
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental model of fracture of functionally graded materials
Eksperymentalny model pękania materiału funkcjonalnie zmiennego
Autorzy:
Jaroniek, M.
Powiązania:
https://bibliotekanauki.pl/articles/280140.pdf
Data publikacji:
2010
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
composites
fracture mechanics
photoelastic method
finite element method
functionally graded materials
Opis:
Fabrication of functionally graded materials (FGM) can be obtained by layeredmixing of two materials of different thermo-mechanical properties with different volume ratios gradually changing from layer to layer such that the first layer has only a few particles of the second phase and the last has the maximum volume ratio of the first phase. Consider a simple model of the functionally graded materials as a multilayered beam bonded to planes having shear modulus Gi and Poisson's ratio [ni]I, respectively, subjected to bending. The behaviour of cracks depends on cracks configuration, size, orientation, material properties, and loading characteristic. The fracture mechanics problem will be approached by making use of photoelastic visualisation of fracture events in the model structure.
Sposób wykonania materiałów funkcyjnie zmiennych -- FGM, polega na nakładaniu (lub napylaniu) kolejnych (możliwie cienkich) warstw. Warstwy te składają się zazwyczaj z dwóch składników o różnych własnościach (mechanicznych, termicznych itp.) np. ciekły metal (plazma) i ceramika. Technologia wykonania jest następująca: najpierw nakłada się warstwę czystego ciekłego metalu, następnie warstwę ciekłego metalu z niewielką domieszką ceramiki, następne warstwy to ciekły metal ze zwiększającą się ilością ceramiki, aż do ostatniej warstwy składającej się z czystej ceramiki. W ten sposób (po zastygnięciu) otrzymuje się powłoki izolacyjne stosowane do komór spalania silników, warstwy termoizolacyjne promów i kapsuł kosmicznych itp. W pracy podano metodę doświadczalno-obliczeniową stanu naprężeń i odkształceń dla kompozytów warstwowych zbudowanych z materiałów gradientowych. Podano także dla takich kompozytów ze szczelinami kryterium zniszczenia. Opracowana metoda jest metoda hybrydową - opierając się na wynikach badań doświadczalnych, opisano stan naprężenia i odkształcenia, stosując metodę potencjałów zespolonych. Na podstawie wyników badań doświadczalnych opisano stan naprężeń i odkształceń dla materiałów liniowo-sprężystych i sprężysto-plastycznych w formie funkcji potencjałów zespolonych. Zastosowanie metody potencjałów zespolonych w postaci szeregów do analizy pól naprężeń umożliwia analizę wyników badań doświadczalnych modeli kompozytów, z uwagi na budowę równań, które w kompleksowy sposób opisują stan naprężenia w formie sumy i różnicy naprężeń normalnych. Przeprowadzone obliczenia i badania mają na celu weryfikację modelu, który można zastosować do obliczeń kompozytów warstwowych.
Źródło:
Journal of Theoretical and Applied Mechanics; 2010, 48, 1; 71-86
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Elongation determination using finite element and boundary element method
Autorzy:
Kisała, P.
Wójcik, W.
Smailov, N.
Kalizhanova, A.
Harasim, D.
Powiązania:
https://bibliotekanauki.pl/articles/226029.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
finite element method
boundary element method
fiber Bragg gratings
elongation distribution
Opis:
This paper presents an application of the finite element method and boundary element method to determine the distribution of the elongation. Computer simulations were performed using the computation of numerical algorithms according to a mathematical structure of the model and taking into account the values of all other elements of the fiber Bragg grating (FBG) sensor. Experimental studies were confirmed by elongation measurement system using one uniform FBG.
Źródło:
International Journal of Electronics and Telecommunications; 2015, 61, 4; 389-394
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł

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