Deformation of EPS Foam Under Combined Compression-Shear Loading: Experimental and Computational Analysis

Expanded Polystyrene (EPS) foam material is widely used as an energy absorption engineering material. Its compression behaviour, both quasi-statically and dynamically, has been studied widely. However, its mechanical behaviour under combined compression-shear loading is poorly understood due to the difficulty of performing such tests. A novel test rig is presented to perform combined compression-shear loading tests in quasi-static loading conditions. Different densities of EPS foam were tested with this apparatus using a universal Instron testing machine. The compressive and shear stresses were obtained and compared, the results show that the shear stress at yield of EPS foam under combined compression-shear loading is much lower compared with the compressive stress at yield. On the other side, the compressive stress at yield can as high as 40% lower compared with pure compression. The FEA simulations were performed using the Abaqus/explicit 6.14 code and it is found the numerical predictions and experimental results agree closely, which indicates that our FE models exhibit good reliability in predicting the response of EPS foam under such loading conditions