Efficient energy absorption of bio-inspired bi-directional gradient hierarchical multi-cell structure

This research proposes a novel bio-inspired bi-directional gradient hierarchical multi-cell (BGHM) structure for efficient energy absorption. Its dynamic crushing performance and energy absorption behaviours are comprehensively investigated through numerical simulations and theoretical analysis. Extensive numerical simulations are conducted on the proposed BGHM structure with varying hierarchical orders and masses. The obtained results demonstrate that the specific energy absorption of the third-order BGHM tube is significantly improved, exhibiting a 110% increase compared to the zero-order BGHM tube. Additionally, the undulation of the loading resistance of the third-order BGHM tube decreased by up to 93.0% when compared to a conventional square tube, highlighting the tremendous potential of BGHM tubes for the development of highly effective energy absorbers. In addition, a new trigger mechanism using the pre-crushing method can eliminate the initial peak crushing force of the BGHM, demonstrating the promising potential of triggers in optimizing the crashworthiness of energy absorbers. Furthermore, a comparative analysis reveals that the specific energy absorption of the BGHM outperforms other existing hierarchical multi-cell square tubes in literature. This underscores the superior energy absorption capabilities of the proposed BGHM. To complement the numerical findings, a theoretical study on the proposed BGHM's mean crushing force is carried out. The results from this theoretical study show excellent agreement with the numerical results and further validate the efficacy of the proposed design. The findings indicate that the bio-inspired bi-directional gradient hierarchy incorporated in the BGHM structure offers promising prospects for advancements in energy absorption technology across various industries.