Dynamic crushing characteristics of bio-inspired minimal surface primitive structures

It has been proven that the triply periodic minimal surface structures (TPMS), a specific type of bio-inspired structures classified as cellular structures with continuous non-self-intersecting surfaces, have excellent energy absorption capability. However, the dynamic crushing characteristics of the TPMS have not been well comprehended. The dynamic response of minimal surface primitive structures under different crushing speeds is numerically investigated in this study. The dynamic crushing stresses of the primitive structure at the loading location and stationary side are measured to investigate the dynamic effect due to the shock wave propagation. Furthermore, the influences of other parameters, i.e., the crushing speed, relative density, and strain rate effect on the crushing stress are also discussed. The obtained results indicate that the plateau stress at the loading location is highly sensitive to the crushing speed while the opposite trend is observed for the plateau stress at the stationary side. It is also found that the primitive structures tend to deform following four distinct mode shapes, i. e., "X" mode, "K" mode, "I1" and "I2" mode, which are dependent on the crushing speed and relative density. Moreover, the energy absorption efficiency is used to define the densification strain, which shows no clear relationship with the relative density. Finally, the empirical models based on the shock wave theory and previous empirical model of honeycomb structures are developed to predict the plateau stress at the loading location and stationary side with/without strain rate effect. The predictions of the proposed analytical models agree well with the numerical results.