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Wyświetlanie 1-15 z 19
Tytuł:
Shape Optimization of Labyrinth Seals
Autorzy:
Aboulaich, R.
Azelmat, K.
Baranger, J.
Souissi, A.
Powiązania:
https://bibliotekanauki.pl/articles/911193.pdf
Data publikacji:
2000
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
optymalizacja
metoda elementów skończonych
shape optimization
hydraulic turbine
Navier-Stokes equations
finite element method
Opis:
In this work, we determine the optimal shape of a labyrinth seal in a hydraulic Francis turbine. The numerical approximation of the optimal shape is obtained using shape optimization techniques. The flow is governed by Navier-Stokes equations. We first prove the existence of an optimal domain, and later we present the computation of the shape gradient which allows us to approximate numerically the optimal domain.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2000, 10, 2; 381-404
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Parallel evolutionary algorithms in shape optimization of heat radiators
Zastosowanie równoległego algorytmu ewolucyjnego do optymalizacji kształtu radiatorów
Autorzy:
Burczyński, T.
Długosz, A.
Kuś, W.
Powiązania:
https://bibliotekanauki.pl/articles/280305.pdf
Data publikacji:
2006
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
coupled thermoelasticity
radiation
finite element method
parallel evolutionary algorithm
evolutionary optimization
shape optimization
Opis:
The paper deals with the application of Parallel Evolutionary Algorithms (PEA) and the Finite Element Method (FEM) in shape optimization of heat radiators. The fitness function is computed with the use of the coupled thermoelsticity modelled by MARC/MENTAT software. The geometry, mesh and boundary conditions are created on the basis of a script language implemented in MENTAT. In order to reduce the number of design parameters in evolutionary algorithms, the shape of the structure is modelled by Bezier curves. Numerical examples for some shape optimization are included.
W pracy przedstawiono zastosowanie algorytmów ewolucyjnych oraz metody elementów skończonych (MES) w optymalizacji kształtu radiatorów. Zastosowano algorytm ewolucyjny, w którym funkcja celu wyznaczana jest w sposób równoległy, więc obliczenia przeprowadzane mogą być na wielu komputerach wieloprocesorowych. Tego typu podejście znacznie skraca czas obliczeń w porównaniu do sekwencyjnego algorytmu ewolucyjnego. Wartość funkcji celu wyznaczana jest na podstawie rozwiązania zagadnienia termosprężystości z wykorzystaniem oprogramowania MES MARC/MENTAT. Przy rozwiązywania zagadnienia bezpośredniego uwzględniany jest radiacyjny strumień ciepła. Wyznaczenie stref zacieniania, niezbędnych do jego wyznaczenia, realizowane jest również za pomocą procesora MENTAT. W celu zmniejszenia liczby zmiennych projektowych przy modelowaniu geometrii radiatora wykorzystano krzywe Beziera. Ponadto praca zawiera przykłady numeryczne optymalizacji dla różnych konfiguracji warunków brzegowych.
Źródło:
Journal of Theoretical and Applied Mechanics; 2006, 44, 2; 351-366
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Finite element modelling and static shape control of a functionally graded piezoelectric beam
Autorzy:
Eshraghi, I.
Powiązania:
https://bibliotekanauki.pl/articles/38697103.pdf
Data publikacji:
2023
Wydawca:
Instytut Podstawowych Problemów Techniki PAN
Tematy:
functionally graded piezoelectric beam
finite element method
shape control
Buildup Voltage Distribution algorithm
Opis:
A finite element model is developed for discretization and analysis of the functionally graded piezoelectric material (FGPM) beam based on the Timoshenko beam theory and assuming linear constitutive relation for the corresponding piezoelectric material behavior. Results obtained using the developed finite element code are compared with the available experimental and numerical results for smart structures with and without graded properties. Static shape control of the beam is conducted using the Buildup Voltage Distribution (BVD) algorithm by implementing this method in the finite element routine. Numerical simulations have been performed to study the performance of the shape control algorithm by optimizing the distribution of the applied voltages. Furthermore, the effect of the number of iterations on the result accuracy as well as the variation of the control voltage distribution with the number of discretized regions and the volume fractions of the constituent material is studied. A fast numerical convergence with good accuracy is observed for the shape control of FGPM beams using the developed method. The proposed technique is a good candidate for the modeling, analysis, and control of smart structures with graded properties.
Źródło:
Archives of Mechanics; 2023, 75, 4; 469-492
0373-2029
Pojawia się w:
Archives of Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Approximation of a Solidification Problem
Autorzy:
Aboulaich, R.
Haggouch, I.
Souissi, A.
Powiązania:
https://bibliotekanauki.pl/articles/908072.pdf
Data publikacji:
2001
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
optymalizacja
metoda elementów skończonych
Stefan problem
free boundary
shape optimization
Euler method
finite element method
Opis:
A two-dimensional Stefan problem is usually introduced as a model of solidification, melting or sublimation phenomena. The two-phase Stefan problem has been studied as a direct problem, where the free boundary separating the two regions is eliminated using a variational inequality (Baiocci, 1977; Baiocchi et al., 1973; Rodrigues, 1980; Saguez, 1980; Srunk and Friedman, 1994), the enthalpy function (Ciavaldini, 1972; Lions, 1969; Nochetto et al.., 1991; Saguez, 1980), or a control problem (El Bagdouri, 1987; Peneau, 1995; Saguez, 1980). In the present work, we provide a new formulation leading to a shape optimization problem. For a semidiscretization in time, we consider an Euler scheme. Under some restrictions related to stability conditions, we prove an L^2-rate of convergence of order 1 for the temperature. In the last part, we study the existence of an optimal shape, compute the shape gradient, and suggest a numerical algorithm to approximate the free boundary. The numerical results obtained show that this method is more efficient compared with the others.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2001, 11, 4; 921-955
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The evolution of the shape of composite dowels
Autorzy:
Lorenc, Wojciech
Seidl, Günter
Berthellemy, Jacques
Powiązania:
https://bibliotekanauki.pl/articles/2172885.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
composite dowel
shear connection
composite bridge
fatigue
FEM
finite element method
hybrid beam
Opis:
Composite dowels have opened new possibilities for engineers designing composite structures. The fundamental and most important characteristic of composite dowels is the shape of the cutting line. It is important to understand why only one particular shape of the cutting line is used in bridge engineering, while so many different shapes have been investigated by many researchers. The essential part of the process of developing composite dowels – the development of the shape of the cutting line – is presented in this paper. The influence of the steel web thickness is presented, and technological problems of steel fabrication are highlighted. The role of empirical experience from the first bridges, push-out tests, and finite element simulations is presented. Assumptions for numerical procedures are given. The distinction between the steel failure and concrete failure modes is introduced for composite dowels. The paper presents how the concept of “shape” was divided into “shape,” “ratio,” and finally “size,” and how, because of the fatigue problems in bridges, all the three factors have emerged to result in the form of shapes that can satisfy the requirements for bridges. Research leading to the invention of the first version of the clothoidal shape is presented.
Źródło:
Studia Geotechnica et Mechanica; 2022, 44, 4; 296--316
0137-6365
2083-831X
Pojawia się w:
Studia Geotechnica et Mechanica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Multiobjective shape optimization of selected coupled problems by means of evolutionary algorithms
Autorzy:
Długosz, A.
Burczyński, T.
Powiązania:
https://bibliotekanauki.pl/articles/202348.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
multiobjective optimization
evolutionary algorithms
multiphysics
coupled field problems
finite element method
Opis:
In present paper an improved multi-objective evolutionary algorithm is used for Pareto optimization of selected coupled problems. Coupling of mechanical, electrical and thermal fields is considered. Boundary-value problems of the thermo-elasticity, piezoelectricity and electro-thermo-elasticity are solved by means of finite element method (FEM). Ansys Multiphysics and MSC.Mentat/Marc software are used to solve considered coupled problems. Suitable interfaces between optimization tool and the FEM software are created. Different types of functionals are formulated on the basis of results obtained from the coupled field analysis. Functionals depending on the area or volume of the structure are also proposed. Parametric curves NURBS are used to model some optimized structures. Numerical examples for exemplary three-objective optimization are presented in the paper.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2012, 60, 2; 215-222
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
FEM numerical analysis of the shape bow cross-section for the rigidity of the wheelset measuring device
Autorzy:
Aniszewicz, Andrzej
Powiązania:
https://bibliotekanauki.pl/articles/215733.pdf
Data publikacji:
2019
Wydawca:
Instytut Kolejnictwa
Tematy:
rolling circle diameter
measurement
reliability
wheelset
finite element method
FEM
Opis:
The article shows the results of a computer simulation using the Finite Element Method (FEM) in order to analyze the infl uence of bows geometry cross-section for the rigidity of the instrument measuring the rolling circle diameter of the wheelset wheels. Two types of bow cross-section were considered, a rectangular shape and a shape of four thin pipes welded together. Th e considered measuring instruments should fulfi l the requirements of the standards ZN-00/PKP-3509-09 and BN-82 3509-13. FEM simulation analysis of the instrument models reveals insuffi cient instrument rigidity and indicates the need to introduce changes in the construction of the existing measuring instruments for measuring the rolling circle diameter of the wheelsets wheels.
Źródło:
Problemy Kolejnictwa; 2019, 182; 107-113
0552-2145
2544-9451
Pojawia się w:
Problemy Kolejnictwa
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the buckling and vibrational response of carbon nanotubes with spiral deformation
Autorzy:
Yengejeh, S. I.
Kazemi, S. A.
Öchsner, A.
Powiązania:
https://bibliotekanauki.pl/articles/281449.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
finite element method
carbon nanotubes
natural frequency
critical buckling load
spiral shape
Opis:
Perfect and spiral models of carbon nanotubes (CNTs) have been simulated based on the finite element method and their vibrational and buckling behavior has been investigated. In order to evaluate their natural frequency and critical buckling load, computational tests have been conducted. It has been concluded that the existence of any geometrical modification in the configuration of perfect CNTs results in a remarkable reduction in the natural frequency and critical buckling load of CNTs. It has been also revealed that the analytical solutions are in good agreement with the finite element simulation results in the cases of perfect and spiral CNTs.
Źródło:
Journal of Theoretical and Applied Mechanics; 2016, 54, 2; 613-619
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Stress concentration resulting from irregular shape of explosively cladded materials connections – FEM simulation
Autorzy:
Kurek, A.
Niesłony, A.
Kurek, M.
Powiązania:
https://bibliotekanauki.pl/articles/387039.pdf
Data publikacji:
2014
Wydawca:
Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Tematy:
FEM
finite element method
explosive cladding
interference zone
metoda elementów skończonych
zgrzewanie wybuchowe
Opis:
The paper contains a numerical analysis of interface zone steel-titanium bimetal obtained by explosive cladding method. Due to the waviness of the zone, and various properties of the constituent material of the materials type contain structural notch. Therefore it is important inter alia in terms of presentation of the results of fatigue are the maximum stresses that occur just in the area of the zone. In the paper the stress concentration factor and the proposed method of modelling the joint zone of a sinusoidal profile, characterized by the same coefficient of stress concentration at the actual profile.
Źródło:
Acta Mechanica et Automatica; 2014, 8, 2; 103-106
1898-4088
2300-5319
Pojawia się w:
Acta Mechanica et Automatica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Calculation of distribution of temperature in three-dimensional solid changing its shape during the process
Autorzy:
Bożek, B.
Mączka, C.
Powiązania:
https://bibliotekanauki.pl/articles/255226.pdf
Data publikacji:
2005
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
parabolic partial differential equations
non-stationary distribution of heat
finite element method
Galerkin method
Opis:
The present paper suplements and continues [2]. Galerkin method for the Fourier-Kirchoff equation in the case when Omega(t) - equation domain, dependending on time t, is constructed. For special case Omega(t) rcup R2 the computer program for above method is written. Binaries and sources of this program are available on http://wms.mat.agh.edu.pl/~bozek.
Źródło:
Opuscula Mathematica; 2005, 25, 2; 169-179
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Shape optimisation of a ventricular assist device using a VADFEM computer program
Autorzy:
Kopernik, M.
Powiązania:
https://bibliotekanauki.pl/articles/307277.pdf
Data publikacji:
2013
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
ventricular assist device
finite element method
optimisation
goal function
multi-scale modelling
metoda elementów skończonych
optymalizacja
komorowe wspomaganie pracy serca
Opis:
The Polish ventricular assist device, POLVAD_EXT, is made of a polymer designed to be covered with a nanocoating of titanium nitride to improve haemocompatibility. A loss of cohesion can occur between the coating and the substrate. An analysis of stress and strain states in a multi-scale model of the blood chamber was performed in the finite element computer program, VADFEM. The multiscale model is composed of a macro model of the blood chamber and a micro model of the titanium nitride (TiN) deposited on the polymer. The finite element method and the goal function, based on the triaxiality factor, are used to solve the problems formulated. The theories of non-linear elasticity and elasto-plasticity are applied. The goal of the paper is to optimise the construction of the POLVAD_EXT with respect to shape parameters.
Źródło:
Acta of Bioengineering and Biomechanics; 2013, 15, 3; 81-87
1509-409X
2450-6303
Pojawia się w:
Acta of Bioengineering and Biomechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Shape optimization of a loudspeaker diaphragm with respect to soun directivity properties
Autorzy:
Christensen, S.
Olhoff, N.
Powiązania:
https://bibliotekanauki.pl/articles/206828.pdf
Data publikacji:
1998
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
akustyka
metoda elementów brzegowych
metoda elementów skończonych
acoustics
boundary element method
finite element method
loudspeaker sound directivity
optimum design
Opis:
This paper presents a novel method for optimizing the directivity of the sound emission from the diaphragm of an electro dynamic loudspeaker. The analysis of the diaphragm is performed by finite element analysis of the structural dynamic behaviour and using the boundary element method for the acoustic analysis. Through optimization of a dead mass distribution on the diaphragm, or of the shape of the mid-surface of the diaphragm, it has been possible to improve its directivity properties for sound emission. Several illustrative examples are presented at the end of the paper.
Źródło:
Control and Cybernetics; 1998, 27, 2; 177-198
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Design and Strength Analysis of Curved-Root Concept for Compressor Rotor Blade in Gas Turbine
Autorzy:
Wdowiński, W.
Szymczyk, E.
Jachimowicz, J.
Moneta, G.
Powiązania:
https://bibliotekanauki.pl/articles/97975.pdf
Data publikacji:
2017
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Lotnictwa
Tematy:
finite element method
turbine engine
rotor disk
rotor blades
blade-disc connection
shape optimization
Opis:
The motivation of the article is fatigue and fretting issue of the compressor rotor blades and disks. These phenomena can be caused by high contact pressures leading to fretting occurring on contact faces in the lock (blade-disk connection, attachment of the blade to the disk). Additionally, geometrical notches and high cyclic loading can initiate cracks and lead to engine failures. The paper presents finite element static and modal analyses of the axial compressor 3rd for the original trapezoidal/dovetail lock geometry and its two modifications (new lock concepts) to optimize the stress state of the disk-blade assembly. The cyclic symmetry formulation was used to reduce modelling and computational effort.
Źródło:
Fatigue of Aircraft Structures; 2017, 9; 137-155
2081-7738
2300-7591
Pojawia się w:
Fatigue of Aircraft Structures
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A study of the influence of ribs shape on the gear transmission housing vibroactivity
Badania wpływu kształtu użebrowania korpusu na wibroaktywność przekładni
Autorzy:
Figlus, T.
Wilk, A.
Madej, H.
Powiązania:
https://bibliotekanauki.pl/articles/374107.pdf
Data publikacji:
2010
Wydawca:
Politechnika Śląska. Wydawnictwo Politechniki Śląskiej
Tematy:
przekładnia
wibroaktywność
metoda elementów skończonych
MES
gear transmission
vibroactivity
finite element method
FEM
Opis:
The paper presents the results of model studies aimed at reducing the vibroactivity of the toothed gear housing. The effect was analyzed of the shape of additional ribs on changes of the forms of vibration of the upper housing plate and on its vibroactivity. Simulations were conducted using the Finite Element Method (FEM). Based on the studies performed, the shape of ribs with dimensions ensuring a reduction of vibroactivity by several dB was determined, with a minor increase of the housing weight.
Praca przedstawia wyniki badan modelowych nad obniżaniem wibroaktywności korpusu przekładni zębatej. Analizowano wpływ kształtu dodatkowego użebrowania na zmiany postaci drgań górnej płyty korpusu oraz na jej wibroaktywność. Symulacje prowadzono z wykorzystaniem MES. Na podstawie przeprowadzonych badań wyznaczono kształt żeber o wymiarach zapewniających obniżenie wibroaktywności o kilka dB, przy niewielkim wzroście masy korpusu.
Źródło:
Transport Problems; 2010, 5, 1; 63-69
1896-0596
2300-861X
Pojawia się w:
Transport Problems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Laboratory experimental analysis on encapsulated stone column
Autorzy:
Tandel, Y. K.
Solanki, C. H.
Desai, A. K.
Powiązania:
https://bibliotekanauki.pl/articles/230339.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
kolumna kamienna
hermetyzacja
geosyntetyk
eksperyment
metoda elementów skończonych
nośność
odkształcenie promieniowe
kształt zdeformowany
stone column
encapsulation
geosynthetic
experiment
finite element method
load carrying capacity
radial deformation
deformed shape
Opis:
The application of stone column technique for improvement of soft soils has attracted a considerable attention during the last decade. However, in a very soft soil, the stone columns undergo excessive bulging, because of very low lateral confinement pressure provided by the surrounding soil. The performance of stone column can be improved by the encapsulation of stone column by geosynthetic, which acts to provide additional confinement to columns, preventing excessive bulging and column failure. In the present study, a detailed experimental study on behavior of single column is carried out by varying parameters like diameter of the stone column, length of stone column, length of geosynthetic encapsulation and stiffness of encapsulation material. In addition, finite-element analyses have been performed to access the radial deformation of stone column. The results indicate a remarkable increase in load carrying capacity due to encapsulation. The load carrying capacity of column depends very much upon the diameter of the stone column and stiffness of encapsulation material. The results show that partial encapsulation over top half of the column and fully encapsulated floating column of half the length of clay bed thickness give lower load carrying capacity than fully encapsulated end bearing column. In addition, radial deformation of stone column decreases with increasing stiffness of encapsulation material.
Źródło:
Archives of Civil Engineering; 2013, 59, 3; 359-379
1230-2945
Pojawia się w:
Archives of Civil Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 19

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