Crushing behavior on the cylindrical tube based on lotus leaf vein branched structure

Abstract

By imitating the structural characteristics of the lotus leaf, a new excellent energy absorption structure named as the leaf vein branched circular tube (LVBCT) is proposed by referring to lotus leaf vein branched structure. The evolution of its cross-section may be controlled by the number of main veins distributed along the circumference (N) and the ratio of radius of inner circle Rinner to radius of outer circle Router (γ). To study the crushing behavior of LVBCTs under axial dynamic crushing, the finite element simulation model established by LS-DYNA is first verified by comparing with the experimental results. Following that, a systematic parametric study on geometric parameters N and γ is carried out with three different wall thicknesses. The mechanical properties of LVBCTs are revealed by analyzing the deformation mechanism and crashworthiness indicators (specific energy absorption per unit mass SEAm and peak crushing force PCF). The numerical results show that the LVBCTs may absorb more impact energy and its energy absorption characteristics are closely related to geometric parameters N, γ and wall thickness t. The LVBCTs with N = 6 and γ of 0.5∼0.7 have better crashworthiness. Furthermore, the numerical results show that the thickness matching between main vein and branch vein has influence on the energy absorption ability. The SEAm of LVBCT is improved by 11.3% when the thickness matching between the main vein and the branch vein is 0.92 mm. The results of this study will be helpful to design novel thin-walled structure with better energy absorption ability.