Finite-element analysis of EPP foam core/self-reinforced PP sandwich structures

In this study, fully recyclable and elastic–plastic deformable sandwich panels were developed by considering the mass production requirements, as well as the lightweighting needs of the automotive industry. Expanded polypropylene (EPP) foam core and self-reinforced polypropylene (PP) thermoplastic composite face sheets were selected to produce sandwich panels. Three-point bending experiments were performed to obtain the flexural behavior of the sandwich panels. Finite-element analysis (FEA) of the sandwich beams was carried out and confirmed by experimental results. Three different EPP foam cores with densities of 65.7, 36.5 and 27.0 kg/m³ were used. The FEA models were built in the Abaqus commercial software in three-dimensional (3D) space, and analyses were performed using 3D elements. The crushable foam material model was selected for FEA from the Abaqus material model database to obtain the best correlation with the foam compression test results. The force–displacement results of the three-point bending FEA results excellently correlated with the experiments. In three-point bending experiments of the sandwich panels, elastic–plastic deformation of the core with indentation failure was observed. The lowest-density foam core sandwich beam showed the highest deformation and energy absorption performance. Also, deflection recovery was observed after load removal for all sandwiches.