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Wyszukujesz frazę "optimal shape" wg kryterium: Temat


Wyświetlanie 1-13 z 13
Tytuł:
Second derivatives and sufficient optimality conditions for shape funetionals
Autorzy:
Eppler, K.
Powiązania:
https://bibliotekanauki.pl/articles/206712.pdf
Data publikacji:
2000
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
optimal shape design
second directional derivatives
sufficient optimality conditions
Opis:
For sorne heuristic approaches to boundary variation in shape optimization the computation of second derivatives of domain and boundary integral functionals, their symmetry and a comparison to the velocity field or material derivative method are discussed. Moreover, for these approaches the functionals are Frechet-differentiable in some sense, because at least a local embedding into a Banach space problem is possible. This allows the discussion of sufficient condition in terms of a coercivity assumption on the second Frechet-derivative. The theory is illustrated by a discussion of the famous Dido problem.
Źródło:
Control and Cybernetics; 2000, 29, 2; 485-511
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An optimal shape design problem for a hyperbolic hemivariational inequality
Autorzy:
Gasiński, Leszek
Powiązania:
https://bibliotekanauki.pl/articles/729253.pdf
Data publikacji:
2000
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
optimal shape design
mapping method
hemivariational inequalities
Clarke subdifferential
Opis:
In this paper we consider hemivariational inequalities of hyperbolic type. The existence result for hemivariational inequality is given and the existence theorem for the optimal shape design problem is shown.
Źródło:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization; 2000, 20, 1; 41-50
1509-9407
Pojawia się w:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Shape optimization in problems governed by generalised Navier-Stokes equations: existence analysis
Autorzy:
Haslinger, J.
Malek, J.
Stebel, J.
Powiązania:
https://bibliotekanauki.pl/articles/970130.pdf
Data publikacji:
2005
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
optimal shape design
paper machine headbox
incompressible non-Newtonian fluid
algebraic turbulence model
Opis:
We study a shape optimization problem for a paper machine headbox which distributes a mixture of water and wood fibers in the paper manufacturing process. The aim is to find a shape which a priori ensures the given velocity profile on the outlet part. The mathematical formulation leads to an optimal control problem in which the control variable is the shape of the domain representing the header, the state problem is represented by the generalised Navier-Stokes system with nontrivial boundary conditions. The objective of this paper is to prove the existence of an optimal shape.
Źródło:
Control and Cybernetics; 2005, 34, 1; 283-303
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Boundary integral representations of second derivatives in shape optimization
Autorzy:
Eppler, Karsten
Powiązania:
https://bibliotekanauki.pl/articles/729245.pdf
Data publikacji:
2000
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
optimal shape design
fundamental solution
boundary integral equation
second-order derivatives
optimality conditions
Opis:
For a shape optimization problem second derivatives are investigated, obtained by a special approach for the description of the boundary variation and the use of a potential ansatz for the state. The natural embedding of the problem in a Banach space allows the application of a standard differential calculus in order to get second derivatives by a straight forward "repetition of differentiation". Moreover, by using boundary value characerizations for more regular data, a complete boundary integral representation of the second derivative of the objective is possible. Basing on this, one easily obtains that the second derivative contains only normal components for stationary domains, i.e. for domains, satisfying the first order necessary condition for a free optimum. Moreover, the nature of the second derivative is discussed, which is helpful for the investigation of sufficient optimality conditions.
Źródło:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization; 2000, 20, 1; 63-78
1509-9407
Pojawia się w:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optimal Shape Design for Elliptic Equations Via Bie-Methods
Autorzy:
Eppler, K.
Powiązania:
https://bibliotekanauki.pl/articles/911209.pdf
Data publikacji:
2000
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
rozwiązanie podstawowe
równanie całkowe
optimal shape design
fundamental solution
boundary integral equation
first-order necessary condition
Opis:
A special description of the boundary variation in a shape optimization problem is investigated. This, together with the use of a potential theory for the state, result in natural embedding of the problem in a Banach space. Therefore, standard differential calculus can be applied in order to prove the Frechet-differentiability of the cost function for appropriately chosen data (sufficiently smooth). Moreover, necessary optimality conditions are obtained in a similar way as in other approaches, and are expressed in terms of an adjoint state for more regular data.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2000, 10, 3; 487-516
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dynamic programming approach to structural optimization problem - numerical algorithm
Autorzy:
Fulmański, P.
Nowakowski, A.
Pustelnik, J.
Powiązania:
https://bibliotekanauki.pl/articles/255706.pdf
Data publikacji:
2014
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
elliptic equations
optimal shape control
structural optimization
stationary Navier-Stokes equations
dynamic programming
sufficient optimality condition
numerical approximation
Opis:
In this paper a new shape optimization algorithm is presented. As a model application we consider state problems related to fluid mechanics, namely the Navier-Stokes equations for viscous incompressible fluids. The general approach to the problem is described. Next, transformations to classical optimal control problems are presented. Then, the dynamic programming approach is used and sufficient conditions for the shape optimization problem are given. A new numerical method to find the approximate value function is developed.
Źródło:
Opuscula Mathematica; 2014, 34, 4; 699-724
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of finite variations to topology and shape optimization of 2D structures
Zastosowanie modyfikacji skończonych w optymalizacji topologii i kształtu konstrukcji dwuwymiarowych
Autorzy:
Bojczuk, D.
Sztebelak, W.
Powiązania:
https://bibliotekanauki.pl/articles/280313.pdf
Data publikacji:
2006
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
2D structures
optimal topology and shape
topological derivative
finite modification
structure evolution
Opis:
The method of simultaneous topology and shape optimization of 2D structures by finite topology modification is presented in the paper. Both, structures in a plane state of stress and bending Kirchhoff's plates are analyzed here. Conditions for the introduction of finite topology modification based on the topological derivative are specified. When the respective condition is satisfied, finite holes and finite variations of existing boundaries are introduced into the structure. Next, standard shape optimization of new holes and variable boundaries is performed. Two basic types of modification are considered here, namely the introduction of holes of a prescribed size and shape and the introduction of holes of an unknown size and shape together with the introduction of finite changes of other boundaries. A heuristic algorithm for optimal design of topology and shape is proposed in the paper. Illustrative examples confirm applicability of the proposed approach.
W pracy rozpatrywana jest metoda jednoczesnej optymalizacji topologii i kształtu konstrukcji dwuwymiarowych przy użyciu skończonych modyfikacji topologii. Rozważania dotyczą zarówno konstrukcji tarczowych pracujących w płaskim stanie naprężenia, jak i płyt Kirchhoffa pracujących w stanie zgięciowym. Przy wykorzystaniu pochodnej topologicznej wyprowadzono warunki wprowadzania skończonych modyfikacji topologii. Gdy spełniony jest odpowiedni warunek modyfikacji, do konstrukcji wprowadzane są otwory o skończonych wymiarach oraz ewentualnie skończone modyfikacje pozostałych brzegów. Następnie wykonywana jest standardowa optymalizacja kształtu otworów i brzegów zewnętrznych. Analizowane są dwa podstawowe typy modyfikacji, a mianowicie wprowadzanie otworów o zadanej wielkości i kształcie oraz wprowadzanie otworów o nieznanej wielkości i kształcie wraz z ewentualną skończoną zmianą pozostałych brzegów. W pracy sformułowano odpowiedni algorytm heurystyczny optymalizacji topologii i kształtu rozpatrywanych konstrukcji. Przedstawione przykłady ilustracyjne potwierdzają przydatność zaproponowanego podejścia.
Źródło:
Journal of Theoretical and Applied Mechanics; 2006, 44, 2; 323-349
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental Modeling to Facilitate Removal of Inclusion Contaminants from the Contact Surface in Transversal Extrusion Processes
Autorzy:
Skorulski, G.
Piwnik, J.
Hościło, B.
Powiązania:
https://bibliotekanauki.pl/articles/379917.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
innovative foundry technologies
innovative foundry materials
extrusion
aluminium alloys
experimental modelling
optimal shape
inclusion
contaminants
innowacyjne technologie odlewnicze
materiały innowacyjne
stopy aluminium
wyciskanie
modelowanie eksperymentalne
Opis:
The paper presents experimental optimization of geometrical conditions regarding the shape of billet’s end pieces in the extrusion process of aluminum alloys. The experiments were performed using appropriately pre-treated plasticine as a substitute material. A special test stand was built using a Plexiglass die in order to make it possible to conduct observations and measurements of the modeled contamination surface. To find the best solution, a great number of shape variants of the billets and of their heating temperatures were experimentally analyzed. An attempt was made to find such a solution that could not only resolve the issue of the removal of contaminants from the contact surface of the pre- heated billets but also develop the least complicated technology of billet fabrication. The test results show how to develop the design process and production technology and also offer advice how to improve the quality of the produced profiles. Finally the authors recommend such a shape for the billets that will ensure effective removal of contaminants from the contact surfaces.
Źródło:
Archives of Foundry Engineering; 2014, 14, 1 spec.; 209-212
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optimal reliability for components under thermomechanical cyclic loading
Autorzy:
Bittner, L.
Gottschalk, H.
Powiązania:
https://bibliotekanauki.pl/articles/205661.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
shape optimization
probabilistic failure times
optimal reliability
Opis:
We consider the existence of optimal shapes in a context of the thermo-mechanical system of partial differential equations (PDE) using the recent approach based on elliptic regularity theory (Gottschalk and Schmitz, 2015; Agmon, Douglis and Nirenberg, 1959,1964; Gilbarg and Trudinger, 1977). We give an extended and improved definition of the set of admissible shapes based on a class of sufficiently differentiable deformation maps applied to a baseline shape. The obtained set of admissible shapes again allows to prove a uniform Schauder estimate for the elasticity PDE. In order to deal with thermal stress, a related uniform Schauder estimate will be derived for the heat equation. Special emphasis is put on Robin boundary conditions, which are motivated by the convective heat transfer processes. It is shown that these thermal Schauder estimates can serve as an input to the Schauder estimates for the elasticity equation (Gottschalk and Schmitz, 2015). This is needed to prove the compactness of the (suitably extended) solutions of the entire PDE system in some state space that carries a C2-Hölder topology for the temperature field and a C3-Hölder topology for the displacement. From this, one obtains the property of graph compactness, which is the essential tool to prove the existence of optimal shapes. Due to the topologies employed, the method works for objective functionals that depend on the displacement and its derivatives up to third order, as well as on the temperature field and its derivatives up to second order. This general result in shape optimization is then applied to the problem of optimal reliability, i.e. the problem of finding shapes that have minimal failure probability under cyclic thermomechanical loading.
Źródło:
Control and Cybernetics; 2016, 45, 4; 421-455
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Control problems for systems described by hemivariational inequalities
Autorzy:
Denkowski, Z.
Powiązania:
https://bibliotekanauki.pl/articles/206594.pdf
Data publikacji:
2002
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
konwergencja G i Gamma
nierówność hemiwariacyjna
operator pseudo-monotoniczny
problem Boltza
wielofunkcja
wrażliwość
zagadnienie poprawnie postawione
zagadnienie sterowania
Clarke subdifferential
control problems (Bolza problem, identification of parameters, optimal shape design)
G and Gamma convergence
hemivariational inequalities
multifunctions
pseudo-monotone operators
sensitivity
well-posedness
Opis:
The paper considers some control problems for the systems described by the evolution, as well as the stationary hemivariational inequalities (HVIs for short). First, basing on surjectivity theorems for pseudo-monotone operators we formulate some existence results for the solutions of the HVIs and investigate some properties of the solution set (like sensitivity; i.e. its dependence on data and operators). Next we quote some existence theorems for optimal solutions for various classes of optimal control like distributed control (e.g. Bolza problem), identification of parameters, or optimal shape design for systems described by HVIs. Finally, we discuss some common features in getting the existence of optimal solutions as well as some "well-posedness" problems.
Źródło:
Control and Cybernetics; 2002, 31, 3; 713-738
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Shape sensitivity of optimal control for the Stokes problem
Autorzy:
Abdelbari, Merwan
Nachi, Khadra
Sokolowski, Jan
Szulc, Katarzyna
Powiązania:
https://bibliotekanauki.pl/articles/2049935.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
Stokes equations
optimal control problem
coupled partial differential equations
shape optimization
shape gradient
Opis:
In this article, we study the shape sensitivity of optimal control for the steady Stokes problem. The main goal is to obtain a robust representation for the derivatives of optimal solution with respect to smooth deformation of the flow domain. We introduce in this paper a rigorous proof of existence of the material derivative in the sense of Piola, as well as the shape derivative for the solution of the optimality system. We apply these results to derive the formulae for the shape gradient of the cost functional; under some regularity conditions the shape gradient is given according to the structure theorem by a function supported on the moving boundary, then the numerical methods for shape optimization can be applied in order to solve the associated optimization problems.
Źródło:
Control and Cybernetics; 2020, 49, 1; 11-40
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optimal design of cylindrical shells
Autorzy:
Nestler, Peter
Schmidt, Werner
Powiązania:
https://bibliotekanauki.pl/articles/729263.pdf
Data publikacji:
2010
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
linear elasticity
shell theory
cylindrical tube
optimal control
shape optimization
Opis:
The present paper studies an optimization problem of dynamically loaded cylindrical tubes. This is a problem of linear elasticity theory. As we search for the optimal thickness of the tube which minimizes the displacement under forces, this is a problem of shape optimization. The mathematical model is given by a differential equation (ODE and PDE, respectively); the mechanical problem is described as an optimal control problem. We consider both the stationary (time independent) and the transient (time dependent) case. P. Nestler derives the model-equations from the Mindlin and Reissner hypotheses. Then, necessary optimality conditions for the optimal control problem are given. Numerical solutions are obtained by FEM, numerical examples are presented.
Źródło:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization; 2010, 30, 2; 253-267
1509-9407
Pojawia się w:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Structure of Optimal Control in Optimal Shaping of the Steel Arch
Autorzy:
Mikulski, Leszek
Jasińska, Dorota
Dąbrowska, Olga
Powiązania:
https://bibliotekanauki.pl/articles/27314818.pdf
Data publikacji:
2022
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
shape optimization
optimal control
steel arch
shaping the cross-section
optymalizacja kształtu
optymalna kontrola
łuk stalowy
kształtowanie przekroju
Opis:
The paper presents the problem of optimal shaping of the H-bar cross-section of a steel arch that ensures minimal mass. Nineteen combinations of nine basic load states are considered simultaneously in the problem formulation. The optimal shaping task is formulated as a control theory problem within the formal structure of the maximum Pontriagin’s principle. Since the ranges of constraint activity defining the control structure are a priori unknown and must be determined numerically, assuming the proper control structure plays a key role in the task solution. The main achievement of the present work is the determination of a solution of the multi-decision and multi-constraint optimization problem of the arch constituting a primary structural system of the existing building assuring the reduction of the structure mass up to 42%. In addition, the impact of the assumed state constraint value on the solution structure is examined.
Źródło:
Civil and Environmental Engineering Reports; 2022, 32, 3; 143--165
2080-5187
2450-8594
Pojawia się w:
Civil and Environmental Engineering Reports
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-13 z 13

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