Quasi-static and dynamic compressive behaviour of sheet TPMS cellular structures

The quasi-static and dynamic compressive behaviour of Triply Periodical Minimal Surface (TPMS) sheet-based cellular structures were evaluated in this research. TPMS cellular structures are novel sheet-based metamaterials, which can offer enhancement in mechanical and other engineering properties compared to strut-based cellular structures. Four different types of TPMS cellular structures were analysed (Diamond, Gyroid, IWP, and Primitive) with four different relative densities, which were additively manufactured by the powder bed fusion technique using stainless steel 316L powder. Two different loading velocities were used in compression testing resulting in engineering strain rates of 0.005 s−1 and 14.2 s−1. Deformation behaviour of dynamic testing was captured using infrared thermography. Stress–strain responses showed a smooth, gradual transition in the stress–strain response from elastic to plastic regions with and an extensive progressive plateau stress. Strain rate hardening contributed to a notable increase in the plateau stress and specific energy absorption of samples. However, no systematic trend was observed. The mathematically designed lattice proposed in this study showed good potential for use in crashworthiness applications and the ability to mathematically control the lattice topology, which can be harnessed in designing functionally graded structures for efficient energy absorption also in modern composite structures.