Wire-Intertwined Hierarchical Lattice Structure: Improved Energy Absorption Stability and Modified Failure Mode

Strut-based lattice structures have widespread applications owing to their excellent performance. Stretching-dominated lattice structures demonstrate a higher energy absorption capacity; however, a strut fracture or buckling failure can cause significant fluctuations in the compressive force. To reduce the fluctuations in the compressive force caused by buckling failure and to improve the energy absorption stability (STB), the authors investigate a wire-intertwined method to fabricate wire-intertwined hierarchical cubic lattice structures (WIHCs) using metallic wires. This method employs a hierarchical design to achieve an elaborate wire configuration. The authors also study the energy absorption behavior and failure mode of WIHC under compression loads using a theoretical model, the finite element method (FEM), and experiments. The authors employ the ratio of the energy absorption to peak stress as the STB and investigate the improvement in the STB of the WIHC compared to that of non-intertwined lattice structures, that is, additive manufactured-metals and polymer cubic lattice structures. The densification strain of the WIHC increases by 25.0%, and its STB improves by 28.3%. This study shows the potential for developing additional wire-intertwined methods for other lattice structures to improve their STB.