Dynamic model of sandwich structure with viscoelastic middle layers

Abstract

Composite materials have been increasingly used in various types of engineering systems such as aeronautics, aerospace and civil engineering to minimize the structural weight. Viscoelastic layer has a level of energy dissipation, therefore it plays an important damping role and improves the dynamic response of the structure. Viscoelastic laminated plates consist of a soft viscoelastic layer which is confined between two identical elastic and stiff layers. In this study a first order shear deformation theory is used to describe the deformation of the composite plate. Simplified forms of the governing equations for symmetric laminated plate are then derived for the flexural mode. The hysteric model of viscoelasticity is used for the mid layer of the composite plate. Results from the present theory are then compared with the results from the Mindlin's Plate Theory for a single layer plate without viscoelasticity for validation of the model. Further FE analysis of the three layer laminated plate with viscoelastic mid-layer is done for the validation of the theoretical model in COMOSL Multiphysics. The results from both the FE model and the theoretical model agree with each other. Attenuation of a particular mode is important because of the amount of a body that may be inspected from a given location depends on it. Since the present study predicts the attenuation quite precisely hence it can be used to choose different modes.