Bionics and design: 3D microstructural characterization and numerical analysis of bamboo based on X-ray microtomography

摘要

Bamboo is considered a natural composite material comprised of a parenchymatic matrix with radially arranged sclerenchyma bundles as reinforcement. Sclerenchyma density gradually varies along the stem, thus endowing the plant with great mechanical resistance. Still, little attention has been given to tridimensional sclerenchyma and parenchyma cell shape and arrangement in numerical analyses of bamboo performance. This study performs a 3D micro-scale characterization and a numerical analysis of bamboo. High-resolution X-ray microtomography (mu CT) stack images of bamboo were used to generate 3D views and tissue relative density and cell shape analyses. Nonlinear finite element analysis (FEA) was held using mu CT-based discretized models of the parenchyma and sclerenchyma. The constitutive properties of the FEA were based on the 3D characterization held on bamboo cells. 3D views of segmented tissues revealed a slight helical structure in vascular bundles of the plant in addition to vascular traces communications between neighboring conducting elements. Numerical compressive strength results were comparable to real sample tests on the literature and failure modes were analyzed. The axial compressive strength of bamboo was due to the arrangement of parenchyma cells gathered as a closed-cell foam matrix and reinforced by helically arranged fiber bundles. mu CT-based FEA was revealed as an interesting approach for assessing the micro-mechanical performance of plants and assisting bionic designs based on bamboo and other monocots. (C) 2016 Elsevier Inc. All rights reserved.