In this paper, transient response analysis of a circular sandwich plate with a functionally graded material (FGM) central disk and two piezoelectric layers is presented. Material properties of the FGM central disk for the circular sandwich plate are assumed to vary through the structural thickness according to a power law and the Poisson’s ratio is assumed as the same constant. Based on the first-order shear deformation theory and geometric nonlinear relationship, the nonlinear motion equations of the circular sandwich plate are formulated by using the Hamilton’s variational principle, then combining with the boundary and initial conditions, the whole problem is solved by adopting the finite difference method, Newmark method and iterative method. Numerical results are presented to illustrate that the volume fraction index, geometric parameters, mechanical and electrical loads have a great influence on transient response of the circular sandwich plate.

We used the generalized differential quadrature (GDQ) method to compute the transient responses of thermal stresses and center deflection amplitude in the magnetostrictive functionally graded material (FGM) square plate under rapid heating acting at its lower surface. We obtained the GDQ solutions in the three-layer of magnetostrictive FGM plates subjected to four simply supported edges. We presented the transient responses of thermal stress and center deflection amplitude of magnetostrictive FGM plates with/without velocity feedback control, respectively, under the effects of the ratio of length to thickness, the power law index, the temperature of environment and the applied heat flux.

In this article, the dynamic response in a multilayered medium is analyzed by Laplace transform technique. The thickness and material constant in each layer are different. The medium is subjected an uniformly distributed loading at the upper surface, and the bottom surface is assumed to be traction-free. The analytical solutions are presented in the transform domain and the numerical Laplace inversion (Durbin's formula) is performed to obtain the transient response in time domain. The effective material concept is usually used to simplify multilayered media in static analysis. The numerical calculations of the transient responses for randomly distributed, periodically distributed, and continuously distributed multilayered media are performed to investigate if the effective material concept is suitable for dynamic analysis.

La dernière décennie a vu apparaître de nombreuses solutions technologiques destinées àaméliorer le confort des automobilistes. L’une d’entre elles, la direction assistéeélectrique (DAE), a considérablement évolué : de plus en plus de véhicules en sontéquipés. L’assistance, délivrée par l’intermédiaire d’un moteur électrique et d’unréducteur roue et vis sans fin, est contrôlée par un calculateur. Cette solution offre despossibilités plus intéressantes en terme de consommation d’énergie que les systèmeshydrauliques encore utilisés sur certains véhicules. La compréhension et lacaractérisation du comportement dynamique des DAE sont devenues des préoccupationsmajeures. En effet, afin de répondre à des exigences vibratoires et acoustiques toujoursplus sévères, le comportement sonore et vibratoire de la direction est étudié. Dans cecontexte, le comportement dynamique de l’ensemble de la DAE est simulé. L’accent anotamment été mis sur la modélisation des deux engrenages présents dans le système(roue-vis sans fin et pignon-crémaillère) et leurs systèmes à rattrapage de jeu. Lamodélisation de la ligne poussoir des DAE est présentée, ainsi que sa validation et sonintégration dans un modèle dynamique d’ensemble. Cette étude consiste en une approche à lafois numérique et expérimentale de la problématique étudiée.

The fundamentals of an approach to solving the control task of robots interaction with a dynamic environment based on the stability of a closed-loop control system are given in this paper. The task is set and solved in its general form. The traditional control concept of compliant robot motion—the hybrid position/force control is discussed. In the paper the proposed control laws ensure simultaneous stabilization of both the desired robot motion and the desired interaction force, as well as their required quality of transient responses. In order to emphasize the fundamental point of this approach in controlling the contact tasks in robotics, the authors have assumed ideal parameters of interacting dynamic systems. The proposed control procedure is demonstrated by one simple example.