Une méthode d'éléments finis mixte pour les équations de Von Kármán
Une méthode intégrale de frontière. Application au Laplacien et à l'élasticité.
The aim of the paper is to give a method to solve boundary value problems associated to the Helmholtz equation and to the operator of elasticity. We transform these problems in problems on the boundary Gamma of an open set of R3. After introducing a symplectic form on H1,2(G) x H-1,2(G) we obtain the adjoint of the boundary operator employed. Then the boundary problem has a solution if and only if the boundary conditions are orthogonal, for this bilinear form, to the elements of the kernel, in a...
Une méthode numérique pour les problèmes d'équilibre de corps hyperélastiques compressibles en grandes déformations.
Une modification du modèle de Mindlin pour les plaques minces en flexion présentant un bord libre
Unexpected solutions of first and second order partial differential equations.
Unicidad local en el equilibrio elástico (piezas longitudinales con leyes no lineales).
Unicité et contrôle pour le système de Lamé
Dans cet article on étudie le problème de l’unicité locale pour le système de Lamé. On prouve qu’on a l’unicité de Cauchy par rapport à toute surface non caractéristique. Nous donnons également deux résultats de densité qui s’applique à la théorie du contrôle pour le système de Lamé.
Unicité et contrôle pour le système de Lamé
In this paper, we study the uniqueness problem for the Lamé system. We prove that we have the uniqueness property across any non characteristic surface. We also give two results which apply to the boundary controllability for the Lamé system.
Uniform a priori estimates for discrete solution of nonlinear tensor diffusion equation in image processing
This paper concerns with the finite volume scheme for nonlinear tensor diffusion in image processing. First we provide some basic information on this type of diffusion including a construction of its diffusion tensor. Then we derive a semi-implicit scheme with the help of so-called diamond-cell method (see [Coirier1] and [Coirier2]). Further, we prove existence and uniqueness of a discrete solution given by our scheme. The proof is based on a gradient bound in the tangential direction by a gradient...
Uniform boundary stabilization of a thermoelastic bar with a nonlinear weak damping
Uniform controllability for Kirchhoff and Mindlin-Timoshenko elastic systems.
Uniform controllability for the beam equation with vanishing structural damping
This paper is devoted to studying the effects of a vanishing structural damping on the controllability properties of the one dimensional linear beam equation. The vanishing term depends on a small parameter . We study the boundary controllability properties of this perturbed equation and the behavior of its boundary controls as goes to zero. It is shown that for any time sufficiently large but independent of and for each initial data in a suitable space there exists a uniformly bounded...
Uniform convergence of mixed interpolated elements for Reissner-Mindlin plates
Uniform stabilization and exact control of multilayered piezoelectric body.
Uniform stabilization for elastic waves system with highly nonlinear localized dissipation.
Uniform stabilization of a coupled structural acoustic system by boundary dissipation.
Uniform stabilization of some damped second order evolution equations with vanishing short memory
We consider a damped abstract second order evolution equation with an additional vanishing damping of Kelvin–Voigt type. Unlike the earlier work by Zuazua and Ervedoza, we do not assume the operator defining the main damping to be bounded. First, using a constructive frequency domain method coupled with a decomposition of frequencies and the introduction of a new variable, we show that if the limit system is exponentially stable, then this evolutionary system is uniformly − with respect to the calibration...
Uniformity and homogeneity of elastic rods, shells and Cosserat three-dimensional bodies.
Uniformity and homogeneity of elastic rods, shells and Cosserat three-dimensional bodies
We present a general geometrical theory of uniform bodies which includes three-dimensional Cosserat bodies, rods and shells as particular cases. Criteria of local homogeneity are given in terms on connections.
Unilateral contact applications using FEM software
Nonsmooth analysis, inequality constrained optimization and variational inequalities are involved in the modelling of unilateral contact problems. The corresponding theoretical and algorithmic tools, which are part of the area known as nonsmooth mechanics, are by no means classical. In general purpose software some of these tools (perhaps in a simplified way) are currently available. Two engineering applications, a rubber-coated roller contact problem and a masonry wall, solved with MARC, are briefly...