Crushing behavior of contact-aided AlSi10Mg sandwich structure based on chiral mechanical metamaterials

Abstract

With additional rotation degrees of freedom, chiral mechanical metamaterials reveal a prospect in impact resistance and energy absorption by both facilitating the bending-dominated characteristics in deformation and enabling possible energy dissipation through contact among unit cells. However, the corresponding structure-property relationships are still understudied considering more complex deformation modes. In this paper, the impact of the compression-to-twist effect of chiral metamaterials on the crushing behavior was systematically investigated. We proposed a design framework of chiral metamaterials enabling the intercellular contact during twisting deformation. Through the manufacture, simulation, and experiment of AlSi10Mg sandwich structures composed of chiral metamaterials, the multi-segment mechanical response of the designed sandwich core to a crush load was demonstrated and discussed. Moreover, the unique deformation and failure mechanism was embodied in the derived specific energy absorption (SEA) and compressive modulus. The proposed metamaterial with a contact-aided twist is light-weight and high in SEA, elucidating a practical way of combining bending-dominated and stretching-dominated lattices. It paves the road for designing metamaterials with graded energy absorption performance, rigid-flexible coupling properties, multi-functional responses, etc.