Dynamic compressive strength and crushing properties of expanded polystyrene foam for different strain rates and different temperatures

Abstract

In this study, static and dynamic compression and crushing tests were conducted on expanded polystyrene (EPS) foam for material characterisation at high strain rates. This was done to obtain the stress-strain curve for different temperatures and densities. An influence of the strain rate on the experimental data was shown. The resulting curves for modelling were extracted from the experimental data, which were obtained from high speed drop tower tests. The methodology for the processing of the experimental data for use in the finite element (FE) modelling was presented. The foam material model of LS-Dyna was used to simulate the dynamic compression process. This model is dedicated to modelling crushable foam with optional damping, tension cut-off, and strain rate effects. The adjustment of the material parameters for successful modelling has been reported. This FE model of EPS foam was validated with experimental data using impact on a "kerbstone" support. This model can be applied for simulation of dynamic loads on a bicycle helmet. It is useful for designing a reliable bicycle helmet geometry for different types of accidents.

A coupled constitutive relation with impulse‐momentum for compressive impact behavior of the expanded polypropylene foam

“…Beckmann and Hohe suggested a probabilistic constitutive model for closed cell foams. Also, other contributions along with constitutive characteristics as well as strain rate dependency of polymeric foams have been found . Those results are well established enough to describe the three stage stress‐strain relationship of foams, that is, linear elastic, plateau, and densification regions, however, they are only working at the constant strain rate cases.…”

A phenomenological constitutive modelling of polyethylene foam under multiple impact conditions

“…It must be mentioned that drop tower test machine is unable to maintain a constant strain rate compared with the quasi‐static compressor. However, drop machine has been proved to be an effective tool to characterize the intermediate strain rate performances of the foam reported in the studies of Jeong et al and Krundaeva et al Displacement‐time relations can be obtained by twice integrating the acceleration‐time curves; meantime force‐time relation can be gained by multiplying the acceleration‐time curves by the mass of the platen. Then, average displacement‐force curve was obtained and converted to engineering stress–strain curve by using specimen dimensions.…”

Effect of crumb rubber on mechanical properties of multi-phase syntactic foams

“…The strain rate effect of syntactic epoxy foam material has been investigated under ambient temperature [12][13][14]. The strain rate effect of expanded polystyrene foam under high temperature has been also investigated [15]. The failure strength of polyurethane foam exhibited nonlinear strain-rate dependency [16,17].…”