Numerical and theoretical analysis of the dynamic mechanical behaviour of a modified rhombic dodecahedron lattice structure

Metallic lattice structures have been widely utilized in different fields such as automobile, aerospace and so on, owing to their superior mechanical properties and energy absorption characteristics. In this paper, the enhanced dynamic mechanical properties of the modified rhombic dodecahedron (RD) lattice structures were investigated systematically through numerical simulation and theoretical analysis. Results indicated that compressive modulus, initial yield strength and normalized specific energy absorption (SEA) of the modified RD lattice structures all exhibited a quadratic growth trend with the increase of relative density beyond following the traditional law. Meanwhile, the plateau stress and normalized SEA exhibited certain sensitivity to the strain rate and almost linearly increased as the loading rate increased. Finally, a modified rigid-perfectly plastic-locking shock wave model was also proposed, and the predicted results of the proposed modified shock wave model were consistent with the simulation results.