A study on the constitutive model and parameter identification of polystyrene plastic foam

Mechanical properties like tensile stress-strain curves of polystyrene plastic foam were measured under different loading conditions, thus the influences of various factors on mechanical behaviors of polystyrene plastic foam were systematically analyzed. The results indicate that the material density, thickness and loading speed have effect on the mechanical properties. The ultimate strength tends to increase as the material density increases and it increases rather much as the loading speed goes up whereas it tends to decrease as the material become thicker. An empirical constitutive model for describing metal materials was proposed for polystyrene plastic foam, and model parameters were obtained by fitting the material compression experimental data performed under different densities, thickness and loading speeds. A comparison made between the calculated and experimental results indicates that the proposed constitutive model may describe the stress-strain relationship of polystyrene plastic foam material rather well within certain loading speeds. The results obtained for polystyrene plastic foam are expected to provide necessary information for cushioning packing structure design.