The present work is as investigation of the transient response of a rectangular three layer sandwich plate with Electro-rheological (ER) core and orthotropic face sheets. ER fluids which are a class of smart materials exhibit reversible changes in their mechanical properties when they are subjected to an electric field. By applying an electric field to the core layer is changed the dynamic characteristics of the structure, the ER layer can be used for vibrations suppressing and reducing the settling time of the sandwich plate subjected to a transient excitation. In this study, an FE model of the structure is developed and a modified direct integration algorithm is used to simulate the impulse response of the proposed sandwich plate. The derived finite element model and the solution procedure are programmed as a code. Since the behavior of electro-rheological materials are different in the pre-yield and post-yield regions, it is necessary to identify the state of the ER material throughout the solution time. According to numerical results which are compatible with previous experimental observations, the produced shear stains in the core is greater than the required strain for exiting the core material from its pre-yield regime. Hence, the core is modeled as a Bingham plastic material. Based on the proposed model, effects of changes in the applied electric filed on the structure settling time and its natural frequencies are represented for different core thicknesses.

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