Abstract
The purpose of this paper is to investigate the applicability of the constrained layer damping theory, which has been widely used for the vibration analysis of sandwich structures with viscoelastic damping layers. This theory proposed by Kerwin contains the following major assumptions : longitudinal direct stresses in the viscoelastic layer are negligible : transverse direct strains in each layer are also neglected ; and all layers displace laterally the same amount. In this paper, excluding these assumptions, the equations of motion of a three-layer sandwich beam are derived applying the two-dimensional theory of elasticity to the deformation of the viscoelastic layer. For simply supported beams, frequencies and loss factors are calculated from the accurate method presented here, and from the approximate method based on the constrained layer damping theory. The analytical results indicate that the approximate method can be used practically in many cases.
