On the use of discontinuous elastomer patches to optimize the damping properties of composite sandwich plates

This study investigates the optimization of a hybrid composite/elastomer sandwich plate structure using a periodical pattern of viscoelastic material. Design variables consist in the thicknesses of the layers, their fiber orientations, the position of the elastomer patches and their geometrical distribution. Damping properties of the hybrid structure are calculated by the Method of Strain Energy (MSE) and the constrained optimization maximizes these properties using the active-set algorithm. Two optimized plates containing patterns embedded or not in a composite matrix are compared with a plate damped by a continuous viscoelastic layer. Results show that optimizing composite plates with patches gives interesting results: damping properties are about ten times the properties of the plates with continuous viscoelastic layers, the patches can be sticked on the external layers of the plate and not internally, and all the strain components in elastomer are involved in damping.