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Tytuł:
Modelling of the heat load in the piston of turbo diesel engine - continuation
Modelowanie obciążeń cieplnych tłoka doładowanego silnika ZS - kontynuacja
Autorzy:
Gustof, P.
Hornik, A.
Jędrusik, D.
Powiązania:
https://bibliotekanauki.pl/articles/374585.pdf
Data publikacji:
2007
Wydawca:
Politechnika Śląska. Wydawnictwo Politechniki Śląskiej
Tematy:
silnik z zapłonem samoczynnym
obciążenie cieplne silnika
COSMOS/M
metoda warunków brzegowych
metoda elementów skończonych
turbo diesel engine
heat load in engine
boundary conditions method
finite elements method
Opis:
In this study the mathematical description of characteristic surfaces of the heat exchange of the piston and temperature distribution of the turbo diesel engine at the beginning phase its work was presented. The computations were performed by means of the two-zone combustion model, the boundary conditions of III kind and the finite elements method (MES) by using of COSMOS/M program.
W niniejszym artykule przedstawiono matematyczny opis charakterystycznych powierzchni wymiany ciepła tłoka oraz rozkład ich temperatury dla doładowanego silnika, z zapłonem samoczynnym w początkowej fazie jego pracy. Obliczenia numeryczne zostały przeprowadzone przy zastosowaniu dwustrefowego modelu procesu spalania [1], warunków brzegowych III rodzaju oraz metody elementów skończonych (MES), za pomocą programu COSMOS/M.
Źródło:
Transport Problems; 2007, 2, 4; 81-86
1896-0596
2300-861X
Pojawia się w:
Transport Problems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical creep analysis of FGM rotating disc with GDQ method
Autorzy:
Zharfi, H.
Toussi, H. E.
Powiązania:
https://bibliotekanauki.pl/articles/280599.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
creep
FGM
GDQ method
rotating disc
boundary conditions
Opis:
Rotating discs are the vital part of many kinds of machineries. Usually, they are operating at relatively high angular velocity and temperature conditions. Accordingly, in practice, the creep analysis is an essential necessity in the study of rotating discs. In this paper, the time dependent creep analysis of a thin Functionally Graded Material (FGM) rotating disc investigated using the Generalized Differential Quadrature (GDQ) method. Creep is described with Sherby’s constitutive model. Secondary creep governing equations are derived and solved for a disc with two various boundary conditions and with linear distribution of SiC particles in pure Aluminum matrix. Since the creep rates are a function of stresses, time and temperature, there is not a closed form solution to these equations. Using a solution algorithm and the GDQ method, a solution procedure for these nonlinear equations is presented. Comparison of the results with other existing creep studies in literature reveals the robustness, precision and high efficiency beside rapid convergence of the present approach.
Źródło:
Journal of Theoretical and Applied Mechanics; 2017, 55, 1; 331-341
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Computations of an unsteady viscous flow in a three dimensional system of ducts. Part I: Formulation of the mathematical problem and numerical method
Autorzy:
Szumbarski, J.
Olszewski, P.
Styczek, A.
Rokicki, J.
Powiązania:
https://bibliotekanauki.pl/articles/280661.pdf
Data publikacji:
2004
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
Navier-Stokes equations
defective boundary conditions
spectral element method
Opis:
Numerical modeling of an unsteady flow of a viscous incompressible fluid inside a branched pipe system is considered. The mathematical formulation is given with special emphasis on inlet/outlet conditions. The equivalent weak form of the initial-boundary value problem is presented. The numerical method based on solutions to particular Stokes problems is proposed and described in some details. Finally, some general remarks about the implementation issues within the framework of the spectral element discretization are made.
W pracy rozważono problem numerycznego wyznaczania nieustalonego przepływu cieczy lepkiej w układzie trójwymiarowych przewodów. Podano sformułowanie wariacyjne zagadnienia uwzględniające uogólnione warunki brzegowe na wlotach/wylotach do obszaru ruchu. Opisano metodę obliczeniową, opartą na zastosowaniu wskaźników Lagrange'a i superpozycji szczególnych problemów Stokesa w każdym kroku czasowym.
Źródło:
Journal of Theoretical and Applied Mechanics; 2004, 42, 1; 21-39
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A modified Fourier-Ritz method for free vibration of rectangular plates with elastic constrains
Autorzy:
Wu, Tao
Chen, Zhao Bo
Qu, Jian Jun
Powiązania:
https://bibliotekanauki.pl/articles/2086961.pdf
Data publikacji:
2022
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
modified Fourier-Ritz method
rectangular plate
free vibration
boundary conditions
Opis:
In this paper, a modified Fourier-Ritz method is used to study free vibration of a rectangular plate with a set of simply supported opposite sides and another set of arbitrary elastic constraints. The influence of different elastic constraint stiffness values on the modal response of the rectangular plate is also analyzed. In order to avoid that the displacement function of the rectangular plate calculated by the traditional method and its derivative may be discontinuous or non-derivable at the boundary, the displacement function is expressed in the form of the sum of standard cosine series and a periodic polynomial function. Compared with the sine series expansion, the convergence of the result is enhanced. Several sets of numerical examples with different boundary conditions are given in the article, the data shows that the results calculated by this method have good accuracy and fast convergence. In addition, this paper also analyzes the boundary conditions and discusses the influence of different spring stiffness values on the setting of boundary conditions. The results can be applied to the setting of general boundary conditions and the study of vibration control of rectangular plates.
Źródło:
Journal of Theoretical and Applied Mechanics; 2022, 60, 1; 77--89
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The effect of model size and boundary conditions on the representativeness of digital material representation simulations of ferritic-pearlitic sample compression
Autorzy:
Perzyński, Konrad
Powiązania:
https://bibliotekanauki.pl/articles/29520075.pdf
Data publikacji:
2022
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
representativeness
digital material representation
finite element method
periodic boundary conditions
Opis:
The main objective of this work is to investigate the representativeness of the digital material representation (DMR) models of ferritic-pearlitic steel generated by the hybrid cellular automata (CA) / Monte Carlo (MC) algorithm. Particular attention is focused on determining the effect of the size of the digital representation model on its representativeness under deformation conditions simulated with the finite element (FE) framework. In addition, the effect of periodic and non-periodic boundary conditions on the deformation behaviour of DMR models is analysed. A dedicated buffer zone approach applied the periodic boundary conditions on non-periodic finite element models. The results of equivalent stresses and strains and their average values are used to evaluate the differences between the models’ predictions.
Źródło:
Computer Methods in Materials Science; 2022, 22, 2; 59-66
2720-4081
2720-3948
Pojawia się w:
Computer Methods in Materials Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical studies on patterning of shear zone in granular bodies
Autorzy:
Tejchman, J.
Powiązania:
https://bibliotekanauki.pl/articles/1954556.pdf
Data publikacji:
2000
Wydawca:
Politechnika Gdańska
Tematy:
localisation
hypoplasticity
polar continuum
boundary conditions
shear zone
finite element method
Opis:
The paper deals with numerical investigations on the patterning of shear zones in granular bodies. The behaviour of dry sand during plane strain compression tests was numerically modelled with a finite element method using a hypoplastic constitutive relation within a polar (Cosserat) continuum. The constitutive relation was obtained through an extension of a non-polar one by polar quantities, viz. rotations, curvatures, couple stresses using the mean grain diameter as a characteristic length. This relation can reproduce the essential features of granular bodies during shear localisation. The material constants can be easily determined from element test results and can be estimated from granulometric properties. The attention is laid on the influence of boundary conditions and the distribution of imperfections in the granular specimen on the formation of patterns of shear zones.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2000, 4, 3; 485-516
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Recent simulation results of the magnetic induction tomography forward problem
Autorzy:
Stawicki, K.
Szuflitowska, B.
Ziolkowski, M.
Powiązania:
https://bibliotekanauki.pl/articles/141095.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
boundary conditions
eddy current testing
finite element method
magnetic
induction tomography
Opis:
In this paper we present the results of simulations of the Magnetic Induction Tomography (MIT) forward problem. Two complementary calculation techniques have been implemented and coupled, namely: the finite element method (applied in commercial software Comsol Multiphysics) and the second, algebraic manipulations on basic relationships of electromagnetism in Matlab. The developed combination saves a lot of time and makes a better use of the available computer resources.
Źródło:
Archives of Electrical Engineering; 2016, 65, 2; 327-336
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical solutions to boundary value problem for anomalous diffusion equation with Riesz-Feller fractional operator
Numeryczne rozwiązanie zagadnienia brzegowego równania anomalnej dyfuzji z operatorem frakcjalnym Riesza-Fellera
Autorzy:
Ciesielski, M.
Leszczyński, J.
Powiązania:
https://bibliotekanauki.pl/articles/280627.pdf
Data publikacji:
2006
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
Riesz-Feller fractional derivative
boundary value problem
Dirichlet conditions
finite difference method
Opis:
In this paper, we present a numerical solution to an ordinary differential equation of a fractional order in one-dimensional space. The solution to this equation can describe a steady state of the process of anomalous diffusion. The process arises from interactions within complex and non-homogeneous background. We present a numerical method which is based on the finite differences method. We consider a boundary value problem (Dirichlet conditions) for an equation with the Riesz-Feller fractional derivative. In the final part of this paper, some simulation results are shown. We present an example of non-linear temperature profiles in nanotubes which can be approximated by a solution to the fractional differential equation.
W pracy zaprezentowano numeryczne rozwiązanie jednowymiarowego równania różniczkowego zwyczajnego niecałkowitego rzędu. Rozwiązanie tego równania może opisywać stan ustalony procesu anomalnej dyfuzji. Proces ten wynika z oddziaływań zachodzących w złożonych i niejednorodnych systemach. Zaprezentowana metoda numeryczna oparta jest na metodzie różnic skończonych. Rozważane było zagadnieriie brzegowe z warunkami Dirichleta dla tego równania z pochodną frakcjalną RieszaFellera. W końcowej części przedstawiono wyniki symulacji. Jako przykład zaprezentowano nieliniowy profil temperatury w nanorurkach, który może być przybliżony przez rozwiązanie frakcjalnego równania różniczkowego.
Źródło:
Journal of Theoretical and Applied Mechanics; 2006, 44, 2; 393-403
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Energy Method for Elastic Problems With Non-Homogeneous Boundary Conditions
Autorzy:
Quintanilla, R.
Powiązania:
https://bibliotekanauki.pl/articles/907887.pdf
Data publikacji:
2002
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
matematyka
weighted energy method
decay estimates
Navier equations
non-homogeneous boundary conditions
Opis:
In this paper we propose the weighted energy method as a way to study estimates of solutions of boundary-value problems with non-homogeneous boundary conditions in elasticity. First, we use this method to study spatial decay estimates in two-dimensional elasticity when we consider non-homogeneous boundary conditions on the boundary. Some comments in the case of harmonic vibrations are considered as well. We also extend the arguments to a class of three-dimensional problems in a cylinder. A section is devoted to the study of an ill-posed problem. Some remarks are presented in the last section of the paper.In this paper we propose the weighted energy method as a way to study estimates of solutions of boundary-value problems with non-homogeneous boundary conditions in elasticity. First, we use this method to study spatial decay estimates in two-dimensional elasticity when we consider non-homogeneous boundary conditions on the boundary. Some comments in the case of harmonic vibrations are considered as well. We also extend the arguments to a class of three-dimensional problems in a cylinder. A section is devoted to the study of an ill-posed problem. Some remarks are presented in the last section of the paper.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2002, 12, 1; 91-100
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dynamic stability of weak equations of rectangular plates
Dynamiczna stateczność słabych równań płyt prostokątnych
Autorzy:
Tylikowski, A.
Powiązania:
https://bibliotekanauki.pl/articles/280859.pdf
Data publikacji:
2008
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
dynamiczna stateczność
metoda Liapunowa
weak formulation
dynamic stability
different boundary conditions
Liapunov method
Opis:
The stability analysis method is developed for distributed dynamic problems with relaxed ssumptions imposed on solutions. The problem is motivated by structural vibrations with external time-dependent parametric excitations which are controlled using surfacemounted or embedded actuators and sensors. The strong form of equations involves irregulari- ties which lead to computational difficulties for estimation and control problems. In order to avoid irregular terms resulting from differentiation of force and moment terms, dynamical equations are written in a weak form. The weak form of dynamical equations of linear mechanical struc- tures is obtained using Hamilton’s principle. The study of stability of a stochastic weak system is based on examining properties of the Liapunov functional along a weak solution. Solving the problem is not dependent on assumed boundary conditions.
W pracy rozszerzono możliwości analizy stabilności układów ciągłych na układy z osłabionymi warunkami nakładanymi na rozwiązania. Układy aktywnego tłumienia drgań cienkościennych elementów płytowych mogą zawierać elementy piezoelektryczne oddziaływujące na konstrukcję.W uproszczonym modelu oddziaływanie to sprowadza się do działania momentów gnących lub sił rozłożonych na krawędziach elementu piezoelektrycznego. Wprowadzenie dystrybucji -Diraca i jej pochodnej prowadzi do analitycznego zapisu obciążenia i wprowadza nieregularności do rozwiązania zadania drgań wymuszonych układu ciągłego. Słabą postać równań płyty otrzymano za pomocą zasady Hamiltona. Badanie stateczności stochastycznych układów w formie słabej jest oparte na analizie funkcjonału Lapunowa wzdłuż słabego rozwiązania. Rozwiązanie zadania jest niezależne od przyjętych warunków brzegowych.
Źródło:
Journal of Theoretical and Applied Mechanics; 2008, 46, 3; 679-692
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A boundary condotions at modeling 1-D pulsating flows in pipes according to the method of characteristics
Autorzy:
Pałczyński, T.
Powiązania:
https://bibliotekanauki.pl/articles/246623.pdf
Data publikacji:
2012
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
1D simulations
Valve boundary conditions
method of characteristics
pulsating flow at pipes
Opis:
At this paper, there were compared three conceptions of boundary conditions and their definition at partially opened pipes. This is typical at inlet and exhaust pipes of internal combustion engines and piston compressors. At an introduction there were listed the current state of affairs at a one dimensional modelling pulsations according to the Method of Characteristics (MOC). Subsequently, there was presented the main idea of MOC. At the third chapter there were presented general guidelines at initial and boundary conditions definition. Next there are three descriptions of the analyzed problem. Firstly, there was presented partially open end phenomena at space and stage plane. Secondly, there was shown the theory of acoustic wave propagation with description of stage waves at analyzed ends of pipe. Lastly, there is a new conception of constant pressure valve boundary conditions, which is the synthesis of the both mentioned earlier. At the fourth paragraph there was shortly presented existing test rig dedicated to research of pulsating flow in pipes. This test rig was built at Flow Metrology Division of Lodz University of Technology [9]. At the second part of this chapter there were shown main assumption of elaborated simulation algorithm at Matlab Simulink environment. Lastly there were discussed simulation results compared with presented conceptions of boundary conditions.
Źródło:
Journal of KONES; 2012, 19, 2; 395-402
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of Boundary Element Method to Solution of Transient Heat Conduction
Autorzy:
Werner-Juszczuk, A.
Sorko, S. A.
Powiązania:
https://bibliotekanauki.pl/articles/387626.pdf
Data publikacji:
2012
Wydawca:
Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Tematy:
metoda elementów brzegowych
przewodzenie ciepła nieustalone
warunek brzegowy
boundary element method
transient heat production problem
periodic boundary conditions
Opis:
The object of this paper is the implementation of boundary element method to solving the transient heat transfer problem with nonzero boundary condition and particularly with periodic boundary condition. The new mathematical BEM algorithm for two dimensional transient heat conduction problem with periodic boundary condition is developed and verified. The results of numerical simulation of transient heat conduction in two dimensional flat plate under non zero initial condition are compared with results obtained with analytical method. Then the practical application of developed algorithm is presented, that is the solution of ground temperature distribution problem with oscillating temperature of ambient. All results were obtained with a new authoring computer program for solving transient heat conduction problem, written in Fortran.
Źródło:
Acta Mechanica et Automatica; 2012, 6, 4; 67-74
1898-4088
2300-5319
Pojawia się w:
Acta Mechanica et Automatica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Finite Element Modelling of a Flow-Acoustic Coupling in Unbounded Domains
Autorzy:
Łojek, Paweł
Czajka, Ireneusz
Gołaś, Andrzej
Powiązania:
https://bibliotekanauki.pl/articles/1953539.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
linearised Euler equations
LEE
FEniCS
finite element method
non-reflective boundary
conditions
open source
Opis:
One of the main issues of design process of HVAC systems and ventilation ducts in particular is correct modelling of coupling of the flow field and acoustic field of the air flowing in such systems. Such a coupling can be modelled in many ways, one of them is using linearised Euler equations (LEE). In this paper, the method of solving these equations using finite element method and open source tools is decribed. Equations were transformed into functional and solved using Python language and FEniCS software. The non-reflective boundary condition called buffer layer was also implemented into equations, which allowed modelling of unbounded domains. The issue, influence of flow on wave propagation, could be adressed using LEE equations, as they take non-uniform mean flow into account. The developed tool was verified and results of simulations were compared with analytical solutions, both in one- and two-dimensional cases. The obtained numerical results are very consistent with analytical ones. Furthermore, this paper describes the use of the developed tool for analysing a more complex model. Acoustic wave propagation for the backward-facing step in the presence of flow calculated using Navier-Stokes equations was studied.
Źródło:
Archives of Acoustics; 2020, 45, 4; 633-645
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical Implementation of the Fictitious Domain Method for Elliptic Equations
Autorzy:
Temirbekov, A. N.
Wójcik, W.
Powiązania:
https://bibliotekanauki.pl/articles/226820.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
elliptic equation
Dirichlet problem
equation with rapidly varying coefficients
computational algorithm
iterative process
fictitious domain method
boundary conditions
Opis:
In this paper, we consider an elliptic equation with strongly varying coefficients. Interest in the study of these equations is connected with the fact that this type of equation is obtained when using the fictitious domain method. In this paper, we propose a special method for the numerical solution of elliptic equations with strongly varying coefficients. A theorem is proved for the rate of convergence of the iterative process developed. A computational algorithm and numerical calculations are developed to illustrate the effectiveness of the proposed method.
Źródło:
International Journal of Electronics and Telecommunications; 2014, 60, 3; 219-223
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Successive iterative method for higher-order fractional differential equations involving Stieltjes integral boundary conditions
Autorzy:
Jankowski, T.
Powiązania:
https://bibliotekanauki.pl/articles/1938598.pdf
Data publikacji:
2016
Wydawca:
Politechnika Gdańska
Tematy:
fractional differential equations with delayed arguments
Stieltjes integral boundary conditions
successive iterative method
convergence
existence of positive solutions
Opis:
In this paper, the existence of positive solutions to fractional differential equations with delayed arguments and Stieltjes integral boundary conditions is discussed. The convergence of successive iterative method of solving such problems is investigated. This allows us to improve some recent works. Some numerical examples illustrate the results.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2016, 20, 1; 99-108
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
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