Viscoelastic material properties' identification using full field measurements on vibrating plates

The paper presents an experimental application of a method leading to the identification of the elastic and damping material properties of isotropic vibrating plates. The theory assumes that the searched parameters can be extracted from curvature and deflection fields measured on the whole surface of the plate at two particular instants of the vibrating motion. The experimental application consists in an original excitation fixture, a particular adaptation of an optical fullfield measurement technique, a data preprocessing giving the curvature and deflection fields and finally in the identification process using the Virtual Fields Method (VFM). The principle of the deflectometry technique used for the measurements is presented. First results of identification on an acrylic plate are presented and compared to reference values. The used theoretical principle only assumes the global equilibrium of the observed part of the coupon. Therefore the identification remains insensible to the parasitic effects of the boundary conditions. This is confirmed by the results of the last presented experimentation.