A finite element solution for plasticity with strain-hardening
Some equilibrium and mixed models in the finite element method
Jak řešit úlohy s nejistými vstupními daty?
Reissnerovske algoritmy 1. druhu v teorii válcových skořepin
Derivation of non-classical variational principles in the theory of elasticity
Generalized variational principles, suggested by Hu Hai-Chang and Washizu or Hellinger and Reissner respectively, are derived on the base of complementary energy respectively. Besides, a short survey of further variational theorems, which follow from the fundamental principles, and the proof of the convergence for a method based on one of them, are presented.
Variational principles in the linear theory of elasticity for general boundary conditions
Mixed boundary-value problem of the classical theory of elasticity is considered, where not only displacements and tractions are prescribed on some parts of the boundary, but also conditions of contact and elastic supports for normal and tangential directions to the boundary surface separately. Classical variational principles are derived using functional analysis methods, especially methods of Hilbert space. Furthermore, generalized variational principles and bilateral estimates of errors are...
Some variational principles for nonlinear elastodynamics
Three variational principles of linear elastodynamics for two initial conditions, recentrly established by M. R. Gurtin, are extended to nonlinear problems with large elastic deformations.
Sur quelques théorèmes variationnels dans la théorie du fluage linéaire
Par la méthode de transformation en problèmes équivalentes de la théorie d'élasticité, on établit deux théorèmes variationnels analogues aux principes du minimum d'énergie potentielle et de Castigliano dans la théorie d'élasticité, pour les corps homogénes isotropes tenant compte à l'hérédité et de l'âge du matérial.
Řešení ohybu kruhově desky metodou Reissnerovských algoritmů 1. druhu
The density of solenoidal functions and the convergence of a dual finite element method
A proof is given of the following theorem: infinitely differentiable solenoidal vector - functions are dense in the space of functions, which are solenoidal in the distribution sense only. The theorem is utilized in proving the convergence of a dual finite element procedure for Dirichlet, Neumann and a mixed boundary value problem of a second order elliptic equation.
Korn's inequality uniform with respect to a class of axisymmetric bodies
The Korn's inequality involves a positive constant, which depends on the domains, in general. We prove that the constants have a positive infimum, if a class of bounded axisymmetric domains and axisymmetric displacement fields are considered.
On a semi-variational method for parabolic equations. II
Несимметричный прогиб пологой сферической оболочки с начальной деформацией под действием внешнего давления
On a semi-variational method for parabolic equations. I
Some -error estimates for semi-variational method applied to parabolic equations
Shape optimization of elastic axisymmetric bodies
The shape of the meridian curve of an elastic body is optimized within a class of Lipschitz functions. Only axisymmetric mixed boundary value problems are considered. Four different cost functionals are used and approximate piecewise linear solutions defined on the basis of a finite element technique. Some convergence and existence results are derived by means of the theory of the appropriate weighted Sobolev spaces.
Optimization of the domain in elliptic problems by the dual finite element method
An optimal part of the boundary of a plane domain for the Poisson equation with mixed boundary conditions is to be found. The cost functional is (i) the internal energy, (ii) the norm of the external flux through the unknown boundary. For the numerical solution of the state problem a dual variational formulation - in terms of the gradient of the solution - and spaces of divergence-free piecewise linear finite elements are used. The existence of an optimal domain and some convergence results are...
Convergence of an equilibrium finite element model for plane elastostatics
An equilibrium triangular block-element, proposed by Watwood and Hartz, is subjected to an analysis and its approximability property is proved. If the solution is regular enough, a quasi-optimal error estimate follows for the dual approximation to the mixed boundary value problem of elasticity (based on Castigliano's principle). The convergence is proved even in a general case, when the solution is not regular.
On a conjugate semi-variational method for parabolic equations
Shape optimization of elastoplastic bodies obeying Hencky's law
A minimization of a cost functional with respect to a part of the boundary, where the body is fixed, is considered. The criterion is defined by an integral of a yield function. The principle of Haar-Kármán and piecewise constant stress approximations are used to solve the state problem. A convergence result and the existence of an optimal boundary is proved.
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