Quasi-static and dynamic out-of-plane crashworthiness of 3D curved-walled mixed-phase honeycombs

Abstract

Honeycombs are widely used in engineering protections due to desirable crashworthiness. However, the gap between peak and mean stresses remains to be narrowed, and effect of interaction between the cells should be enhanced. To break these limits, novel three-dimensional curved-walled mixed-phase honeycombs are proposed in this paper. The specimens manufactured by three-dimensional printing method using 316L stainless steel are used to conduct out-of-plane crushing experiments, and finite element method simulations are carried out by ABAQUS/Explicit. According to experimental and simulation results, theoretical model is established based on the Simplified Super Folding Element theory to estimate the out-of-plane effective mean stress. From the results, the proposed honeycombs display efficient progressive folding mode and desirable mechanical properties, and the gap between peak and mean stresses is effectively narrowed. Compared with traditional straight-walled honeycomb, total energy absorption, specific energy absorption, energy absorption efficiency and force efficiency can be enhanced respectively by 57.8%, 33.8%, 3.4% and 55.3% after implementing 3D curved-walled mixed-phase design, which can be further improved by parameter optimization and thickness gradient design. The work represents an effective approach for designing and optimizing high-performance honeycombs through curved-walled design and mixed-phase mechanism.