Parametric instability regions of a soft and magnetorheological elastomer cored sandwich beam

Present work deals with the study of parametric instability regions of a three-layered, symmetric sandwich beam with conductive skins subjected to periodic axial load. In the core layer, a magnetorheological elastomer (MRE) patch is placed in between two soft viscoelastic patches. The governing equations of motion of the system have been derived, and the parametric instability regions for simple and combination resonances have been investigated for simply supported, clamped-pinned, clamped-guided, and clamped-free end conditions by modified Hsu's method. The instability regions of the system with and without MRE patch, with different magnetic field strengths and permeability of skin materials have been studied. The advantages of using MRE to actively control the vibration of the sandwich beam have been demonstrated. (C) 2009 Elsevier Ltd. All rights reserved,