Finite element analysis of expanded polystyrene foam under multiple compressive loading and unloading

In this paper, finite element (FE) simulation of multiple compressive loading and unloading of expanded polystyrene (EPS) foam used in packaging is studied in detail. Results of FEA packages ABAQUS and LS-DYNA are compared to compression test results and cushioning diagrams for multiple loadings. Foam package designers can use crushable foam material model of ABAQUS and low density foam material model (MAT 57) of LS-DYNA to accurately predict maximum deceleration, force, and displacement for first loading, but FEA packages need improvement for the case of unloading and reloading. ABAQUS overpredicts maximum deceleration, force, and displacement for the same amount of absorbed energy at each loading step. LS-DYNA gives more accurate results if parameters for controlling shape and hysteresis of unloading and reloading in MAT 57 are calibrated using test results, but its evaluation of force and displacement in elastic region and residual deformation after unloading should be improved.