Modeling of the local anisotropic mechanical foam properties in polyisocyanurate metal panels using mesoscale FEM simulations

Abstract

The local anisotropic mechanical foam properties of continuously produced polyisocyanurate metal panels were investigated. The main focus was the analysis of the anisotropic cell structure. Based on these investigations, a mesoscale FE-model of a representative volume element (RVE) was validated, which can provide a prediction of the mechanical properties of anisotropic foam structures with varying aspect ratios and orientations of the cells based on defined ellipsoid packings and an anisotropic tessellation model. During the validation of the model, the parameters mesh size, RVE size and strut partitioning were investigated. Due to the anisotropic cell structures, a method was developed to determine a directional RVE size, which has distinct advantages over cube-shaped RVEs. Finally, a comparison of experimental to numerical results was performed. Both in the experiment and the simulation, the structures show a strongly anisotropic behavior, whereby the degree of anisotropy tends to be slightly underestimated in the simulation. Despite small deviations, the simulation results are in good agreement with the experimental data. Accordingly, this simulation model is suitable for an estimation of the anisotropic mechanical foam properties.