Modal numerical-experimental identification method for characterising the elastic and damping properties in sandwich structures with a relatively stiff core

In this paper, a mixed numerical-experimental identification procedure for characterising the storage and loss properties in sandwich structures with a relatively stiff core is developed. At the computational level, the proposed method is based upon an original structurally damped shell finite element model derived from the higher-order shear deformation theory and, at the experimental level, upon an accurate contact-free measurement setup with a loudspeaker-based excitation and a scanning laser interferometer for capturing the time responses. From the modal information extracted from two specimens with different geometries, the procedure allows the simultaneous estimation of the skin and core constitutive parameters through adequate objective functions measuring the discrepancy between the experimental data and the numerical predictions. For validation purposes, the method is then applied to two test cases for which all the influent properties could be estimated with a fairly good accuracy.