Validating the modeling of sandwich structures with constrained layer damping using fractional derivative models

The effect of the damping insertion due to viscoelastic material (VEM) on the dynamic behavior of aluminum panels is assessed in this work. Dynamic mechanical analysis tests are carried out, aiming at characterizing the rheological behavior of a VEM compound. The time-temperature superposition principle is applied and the VEM compound master curve is built over a large frequency range. The parameters of the fractional derivative model are identified from the obtained master curve, and then input in the model. A distributed coating of constrained VEM applied to a homogeneous aluminum plate is considered in this study. In a first step, the responses of this sandwich structure are calculated by using finite element method (FEM). Free and clamped boundary conditions configurations are modeled. In a second step, tests are performed using the KULeuven test facilities by reproducing the same modeled configurations and the experimental frequency response functions (FRF) are measured. To validate the built FEM models, numerical vs. experimental FRF comparisons are done. Despite a slight underestimation of the damping, good agreements were observed in the whole frequency range.