Crashworthiness analysis of bioinspired hierarchical gradient multicell tubes under axial impact

Hierarchical structures and gradient structures have become research hotspots due to their excellent crashworthiness. However, hierarchical gradient structures that combine hierarchical structures and gradient structures are rarely reported. Inspired by the gradient distribution of biological structure vascular bundles and the excellent energy absorption capacity of hierarchical structures, this paper innovatively combines hierarchical structures and gradient structures to propose a new type of bioinspired hierarchical gradient multicell tube (BHGMT). Crashworthiness studies have shown that the high-order BHGMT has a much better crashworthiness than the low-order BHGMT. The specific energy absorption of the 4th order BHGMT under the same mass is 216.26% that of the 0th order BHGMT. A comparison with other existing hierarchical structures under the same mass conditions shows that the proposed hierarchical gradient structure also has better crashworthiness. Subsequently, the systematic development of the influence of structural parameters such as hierarchy, section thickness, and crisscross rib thickness on the parameterization of BHGMT was carried out. Finally, theoretical research on the mean crushing force of the 3rd order BHGMT was carried out, and the theoretical solution was shown to be in agreement with the numerical simulation results. • Bioinspired hierarchical gradient multicell tubes are proposed to enhance crashworthiness. • Introduction of hierarchical gradients can effectively improve various crashworthiness indicators. • The influence of different crisscross ribs thickness on crashworthiness is studied. • A theoretical model is proposed to predict the mean crushing force of bioinspired hierarchical gradient multicell tubes.