Node-reinforced hollow-strut metal lattice materials for higher strength

Intricate hollow-strut metal lattices are novel cellular materials or metamaterials. However, their hollow nodal regions often lead to premature failure under stress. This study reports a design strategy to substantially improve the strength of hollow-strut metal lattices by applying nodal reinforcement. The proposed nodal reinforcement designs increased the yield strength of hollow-strut Ti-6Al-4V cubic lattices by up to 144% and elastic modulus by up to 113% with a modest 21% increase in density compared to the unreinforced lattices. In addition, a 42% increase in peak stress was observed when compared to solid-strut Ti-6Al-4V cubic lattices of similar densities. These properties exceeded the empirical upper limits of the Gibson-Ashby model for cellular metallic materials, thus extending the property envelope. Distinct failure modes were observed for the proposed nodal reinforce-ment designs. Numerical analysis clarified their role in determining the deformation response.

Automated summary

This study presents a design strategy to improve the strength of hollow-strut metal lattices by applying nodal reinforcement. The proposed designs significantly increased the yield strength and elastic modulus of Ti-6Al-4V cubic lattices, while still maintaining a modest increase in density. Compared to solid-strut Ti-6Al-4V cubic lattices, the reinforced lattices exhibited higher peak stress and exceeded the upper limits of the Gibson-Ashby model for cellular metallic materials.