MECHANISMS IN DAMPING OF MECHANICAL VIBRATION BY PIEZOELECTRIC CERAMIC POLYMER COMPOSITE-MATERIALS

The piezoelectric ceramic (piezoceramic) component of a polymer-piezoe lectric ceramic composite converts mechanical energy into electrical e nergy and this electrical energy is dissipated as heat in a load resis tance, R(x), simulated by a shunted resistance, but provided in practi ce by a conductive polymer composite matrix. The composite therefore d issipates the input mechanical energy via the damping mechanism provid ed by piezoelectric ceramic-conductive matrix material, as well as the conventional viscoelastic damping provided by the polymer. Mathematic al models have been developed to characterize the damping behaviour of the composites, and the maximum damping ratio of composites can be as high as 23%. A two degrees-of-freedom (2DOF) experimental setup was d eveloped to test the validity of the models. The experimental results are in good agreement with the theoretical predictions.