Constrained Layer Damping of Initially Stressed Composite Beams Using Finite Elements

Abstract

This paper presents the development of an efficient finite element model for the analysis of laminated composite beams treated by a constrained viscoelastic layer. The formulation presented includes the ability to model a structure about preloaded con figurations. Since most of the damping ability is due to the shearing of the viscoelastic layer, the model is designed to represent this aspect accurately. An offset beam, shear- deformable element, which is specially suited for modeling such laminated beams is pre sented. The viscoelastic layer is modeled by using two-dimensional plane finite elements which are compatible with the beam elements. In case of a structure with initial load, the final equations are linearized so that first increment of motion, the part due to the initial load is linear, and the second, the part due to the dynamic load is linearized. System damping and tip displacement are compared with existing approximate results and experi mental data whenever possible. Results confirm that dynamic response is substantially im proved by use of such damping treatments, and give some useful information regarding de signing a structure for high damping using constrained damping treatments.