Uncertainties in nonlinear structural dynamics.
Unconditionally stable mid-point time integration in elastic-plastic dynamics
The dynamic analysis of elastoplastic systems discretized by finite elements is dealt with. The material behaviour is described by a rather general internal variable model. The unknown fields are modelled in terms of suitable variables, generalized in Prager's sense. Time integrations are carried out by means of a generalized mid-point rule. The resulting nonlinear equations expressing dynamic equilibrium of the finite step problem are solved by means of a Newton-Raphson iterative scheme. The unconditional...
Unconstrained finite element for geometrical nonlinear dynamics of shells.
Une justification de modèles de plaques viscoplastiques
Une justification des équations de la thermoélasticité des poutres à section variable par des méthodes asymptotiques
Une justification d'un modèle non linéaire en théorie des plaques
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.