Modeling the deformation behavior of polymer sandwich structures with inhomogeneous core

Abstract

Polymer sandwich structures become widely used in the transportation industry due to their high bending stiffness and strength combined with low weight. In the conceptual design phase, it is essential to model the mechanical behavior of the sandwich properly in full-vehicle scale in order to analyze different design variants effectively. In this paper, a finite element modeling method is shown. The method is introduced on a sandwich structure with glass fiber reinforced, vinyl-ester matrix composite face-sheets and a PET foam as core material with an inhomogeneous structure. To model the sandwich panel with layered shells, where the core material is a single layer, equivalent stiffness constants of the inhomogeneous core are needed. To determine these constants, a detailed finite element model was created and virtual tensile and shear tests were performed. On the other hand, an analytical method was also shown. By applying the Voigt- and Reuss-rule on the inhomogeneous core, the needed stiffness constants can also be determined properly. Results of the two methods were compared and they showed a good correlation. Validation of the model was performed via comparing the results of the 4-point bending experimental tests and the simulation results.