Instability of nonlinear viscoelastic plates

This paper investigates the instability of an isotropic, homogeneous, simply supported rectangular plate subjected to a prescribed periodic in-plane load. The material is assumed to be viscoelastic and obey the Leaderman nonlinear constitutive relation. The equation of motion is derived as a nonlinear integro-partial-differential equation, and is simplified into a nonlinear integro-differential equation by the Galerkin method. The averaging method is developed to establish the condition of instability. Numerical results are presented to compare with the analytical ones. 2004 Elsevier Inc. All rights reserved.