Characterization of the Tensile Behavior of Expanded Polystyrene Foam as a Function of Density and Strain Rate

Expanded polystyrene (EPS) foam is a material, frequently used in a range of applications for its good energy absorption, thermal insulation, durability, and acoustic absorption. In this wide range of applications, the material undergoes a variety of loads that can extend from static to dynamic. When it comes to crush applications, these loading profiles create the need of well-defined compression and tensile properties for a range of densities and strain rates. Herein, static and dynamic tension tests are conducted on EPS foam dog-bone samples for material characterization. The target of the study is to obtain stress-strain curves for a range of densities spreading from 60 to 120 g L-1. For the low-strain rates, tensile testing machines are used, whereas for the high-strain rates, a modified drop tower set-up is used. The influence of the strain rate on the stress-strain behavior, the dynamic strength, Young's modulus, and energy absorption capacities for different foam densities is measured. Furthermore, the experimental results for each density are compared with the predictions of Avalle's model for crushable foams to evaluate the validity of the model. The quality of fit obtained between experimental and theoretical is between 70% and 97% depending on the strain rate.