Influence of microstructure on the dynamic behavior of a polyurethane foam with the material point method

Polymer foams have many industrial applications because of their good mechanical properties combined with low material density. However, their study and the prediction of their behavior is challenging due to the massive influence of their complex microstructure. This paper focused on a polyurethane foam containing 70 vol% of porosity and aims at determining its behavior when submitted to large deformations under dynamic compressive loads. A model based on the material point method was set to study the whole stress–strain relationship of representative realistic foam sample, obtained from CT-scans. The dynamic model was validated to compression results from Split Hopkinson Pressure Bar experiments allowing the study of a shock due to a container fall. Direct influence of the microstructure was then evaluated. We first added virtual realistic manufacturing defects on the geometry and then studied the foam behavior of fully computer-designed microstructures. Recent developments in additive fabrication make the manufacturing of such structures possible and would widen the possibilities of virtually optimizing material designs.