Particle reinforced thermoplastic foams under quasi-static compression

Polymer foams are widely used as the core materials for lightweight sandwich structures. Particle reinforcement can be added into polymer foams to enhance their mechanical properties. In this study, particle reinforced foams were manufactured from Linear Low-Density Polyethylene (LLDPE) powder and cellular ceramic particles. Quasi-static compressive responses of the particles reinforced LLDPE foams were measured at selected volume fractions of polymer and particle reinforcement. The experimental measurements have revealed that the reinforcement enhances the elastic modulus, the yield strength and the energy absorption capacity. Analytical predictions of Young's moduli and yield strengths were obtained based on existing theoretical models to interpret the experimental measurement. Finite element (FE) simulations were conducted to understand the reinforcing mechanisms. The FE model was able to predict the measured compressive responses of the foam samples, which captured the complex interaction between particle reinforcements and the hollow cells of the foams. During the loading, the foam matrix around the particle reinforcement is densified or close to being densified while the foam matrix around hollow spherical cells remains undensified, which suggests that hollow spherical cells are stabilised by particle reinforcements. The studies of the size effects of particle reinforcements and hollow cells suggest that the simulation results were not very sensitive to the selected ranges of diameters.