Abstract:In this paper, we examined experimentally the quasi-static uniaxial compressive behaviors of a single EPS foam particle and an assembly of many enclosed EPS particles at different loading rates. As a representative light-weight closed-cell foam, the mechanical behavior of EPS particle is strongly influenced by the gases enclosed in the cell. The contribution of the gas inside the foam cells is analyzed in this paper. For a single foam particle, the contribution of the internal gas on its compressive behavior can be described using a gas model proposed by Ashby et al. A constitutive relationship, considering both effects of the inter gas and the loading rate, is proposed for the compressive behavior of a single EPS particle. For an assembly of enclosed EPS particles, it is shown that both the internal gas and the inter-particle gas affect the mechanical behavior of the assembly. A constitutive relationship using the apparent density of the assembly as an internal variable is proposed for describing the mechanical behavior of the assembly.