The damping properties of elastically supported sandwich plates

Abstract The concept of damped normal modes is used to determine the loss factors and energy dissipation of rectangular three-layer plates with damped viscoelastic cores and elastic boundary members along one pair of opposite edges. The other edges are taken to be simply supported. The differential equations of motion for the modes of a two-dimensional flat plate are first set up, together with the mathematical boundary conditions for edges attached to beams which offer elastic torsional and flexural constraint. Boundary conditions associated with rigid rivets through the plate edges, preventing local core distortion, are also derived. The differential equations are solved in closed form and an iterative method is presented for determining the loss factors and resonant frequencies of the modes. Computer studies and results are. described which show how the damping of the fundamental modes is influenced by the elastic constraints and edge riveting.