Dynamic Behaviour of the Laminated Sandwich Plate with a Stepwise Graded Viscoelastic Core

In this paper, the blast induced vibrations of sandwich plates with stepwise graded core are studied experimentally and numerically. The main objective is to enhance the damping characteristics of sandwich structures. For this purpose, a laminated sandwich plate is manufactured with the wet hand layup technique. The plate has four layers of bidirectional glass epoxy face sheets and a viscoelastic core from three different material layers. Air blast is obtained by compressing the air in a tube and then suddenly expanding the compressed air by rupturing of a membrane in front of the tube. The pressure pulse is impinged on the sandwich panel. Miniature pressure transducers and strain gauges are used to measure blast load and strain, respectively. In the numerical side of the study, an ANSYS finite element model is generated using the laminated shell element with sandwich option. A pressure function is approximated analyzing the experimental pressure data in the time domain and space domain. The strain-time history results obtained from the experimental study and numerical analysis are compared and a good agreement between the results is found.