Abstract:

Lightweight structures can offer many enhanced mechanical characteristics, including load-bearing capability and impact resistance. However, achieving a high specific energy absorption (SEA) and a stable force level is challenging. Here, to overcome these limitations, a novel collapse-resistant structure of the metal foam-filled sandwich tube (MFFST) under free internal inversion is proposed. According to the energy conservation, an analytical model is established to predict the inversion force of the MFFST. The numerical simulations are conducted, and the analytical model captures the numerical results. In addition, the effects of the parameters on the free internal inversion of the MFFST are discussed in detail. It is demonstrated that increasing the yield stress {\sigma }_{\text{s}}, the average diameter D₂, and the total thickness T_{\text{all}}^{\prime } of the metal inner-outer tubes improves the mean crushing force (MCF) and SEA of the free internal inversion device almost linearly.

Key words: collapse-resistant structure, free internal inversion, metal foam, sandwich tube, load-carrying capacity