Dynamic response of arc-shaped bamboo sheets during flattening process

The crack-free flattened bamboo board has gained extensive attention recently because of its high utilization, environmentally-friendliness, and excellent mechanical properties. However, previous reports on bamboo flattening technology have mainly focused on exploring the optimal softening parameters to obtain crack-free flattened bamboo boards, ignoring the changes in surface stress and mechanism of plastic deformation of arc-shaped bamboo sheets during the flattening process. Additionally, the influence of the this process on the cell walls of different parts of the bamboo culm is still not clear due to the heterogeneous distribution of vascular bundles in the material. Thus, in this study, we investigated the effects of pre-treatment parameters on the micro-morphology, chemical compositions, chemical functional groups, macro-physical/mechanical properties, micro-mechanical properties, and surface stress of untreated and treated arc-shaped bamboo sheets. The surface stress of arc-shaped bamboo sheets during the flattening process was analyzed by finite element analysis (FEA) using ABAQUS. The results show that the modulus of elasticity of the inner zone (BI) of bamboo increases from 14.3 GPa to 16.3 GPa, while the hardness of BI increases from 0.45 GPa to 0.52 GPa. The flattened bamboo board exhibits superior anti-mildew properties to those of the untreated bamboo samples due to the heat treatment.