Design and modeling of bamboo biomorphic structure for in-plane energy absorption improvement.

[Display omitted] • Parametric design inspired by bamboo microstructure with improved EA, and CFE. • Bamboo Biomorphic Structure (BBS) showed significantly higher densification strain. • BBS design showed uniform stress distributed across the vertically angled beams. • Higher density distribution within biomorphic layers improved the collapse stress. • BBS-GS showed a stepwise deformation, and absorbed impact energy more efficiently. Bamboo cell wall exhibits a microscopically graded architecture, and micro-layer distributed cells around individual cell walls, which leads to the preferred mechanical properties of bamboo for impact loading. This work proposes a cellular structure, as called Bamboo Biomorphic Structure (BBS), which is a functionally graded honeycomb cellular structure inspired by the microstructure of bamboo and manufactured using fused filament fabrication (FFF). It is hypothesized that, by introducing bamboo biomorphic micro-unit cells, including a range of thickness step differences within an individual honeycomb unit cell, the successive stages of deformation of the honeycomb structure can be controlled, making the system absorb impact energy more efficiently. Characterization of the designed structures was conducted under in-plane quasi-static loading conditions, and then evaluated using a nonlinear finite element commercial code LS-DYNA. The proposed gradient BBS showed higher absorbed impact energies by four times compared with the conventional Honeycomb structure. The proposed parametric design would aid engineering design principles for the development of a novel biomorphic cellular structure, which has the potential for large-scale manufacturing of efficient energy-absorbing engineering structures. Such an energy-absorbing structure can help improve the lightweight structure design for various applications, including automobiles and aircrafts, while ensuring safety under impact load. [ABSTRACT FROM AUTHOR]