Crashworthiness analysis of hexagonal hierarchical gradient tubes with axial variable thickness inspired by tree fractal structure

Abstract

Inspired by the tree fractal structure, a novel hexagonal hierarchical gradient tube with axial variable thickness (HHGAVT) is proposed and its crashworthiness performances are systematically investigated. Results show that when the axial variation coefficient of wall thickness k > 0, the peak crushing force (PCF) of HHGAVT will significantly decrease meanwhile the energy absorption maintains at a high level compared with the referenced structures under the same mass. When k > 0, the PCF and CFE of HHGAVT have absolute advantage compared with the uniform wall thickness tube. The crashworthiness performance can further increase by rational designing the distance factor δ.