Exploring the dynamic response and energy dissipation capacity of functionally graded EPS concrete

In this study, the concept of functionally graded expanded polystyrene (EPS) concrete is developed to improve the protective capabilities offered by lightweight concrete. First, laboratory tests including Split Hopkinson Pressure Bar and Direct-impact Hopkinson Pressure Bar were conducted to explore the dynamic responses of four representative EPS graded modes. Second, a mesoscopic model was built and verified based on the experimental data to consider the loading scenarios which are of engineering interest. Third, with the help of the specific energy absorption method, the energy dissipation capacity of functionally graded EPS concrete was discussed. Test results show that, due to the quick establishment of the stress equilibrium state, functionally graded EPS concrete presents a poorer mechanical performance compared with homogenous EPS concrete and no obvious difference was found in the dynamic responses of four graded modes. When subjected to the loading velocity which are of engineering interest, the graded mode that set the stronger layer at the input surface and the weaker layer at the output surface could exhibit a superior impact resistance ability and reduce the damage to the protected structure. The graded mode can be used to design the best energy dissipation capacity of material with respect to a given loading condition. These findings provide valuable suggestions in the investigation of high-performance protective material. (C) 2019 Published by Elsevier Ltd.