Additive-manufactured hierarchical multi-circular lattice structures for energy absorption application

In this work, a new hierarchical lattice design is proposed by replacing the original straight beams of face-centered cubic (FCC) lattice with a string of higher-level circular beams from the perspective of forming more plastic hinges to improve the energy absorption capacity. The quasi-static compression behavior of our proposed lattice is thoroughly investigated by finite element simulation, theoretical modeling and experimental testing. The experimental specimens made from 316L steel are additively manufactured using the selected laser melting technique. Satisfactory agreement is achieved between the theoretically, numerically and experimentally obtained SEA. It indicates that the proposed lattices have better energy absorption than the conventional FCC lattice. Parametric studies are carried out to investigate the influence of various geometric parameters and indicate that the specific energy absorption and the crushing force efficiency can be simultaneously enhanced by the proposed hierarchical design with proper number of higher-level circular beams. In addition, the auxetic effect is exhibited by the new lattice structures, in accordance with the enhanced energy absorption properties.