Abstract:

Objective: The excellent flexibility of bamboo is due to its microstructure. Having a deeper understanding of the flexibility of bamboo from the micro-level and exploring the morphological changes of bamboo under bending is of important significance. It might provide some bases for the bamboo bending mechanisms and its utilization. Method: Bamboo strips were taken as the research object. The morphological changes of parenchyma cell in the tensile layer were observed by scanning electron microscope(SEM) during cycle loading. For this purpose, parenchyma cell deformation, stress-strain curves of parenchyma cell and parenchymatous tissue, as well as the changes of the cell recovery were analyzed. The deformation of parenchyma cells among different portions was also evaluated. Result: With the increase of the load, parenchyma cell in the tensile layer was stretched in the longitudinal direction, wherea the cell was slightly compressed in the radial direction. The parenchyma cell recovered after unloading. Crease occurred among the parenchyma cells when the bamboo strip was bending. The maximal length strain and width strain of parenchyma cell reached 1.03% and 0.71%, respectively. At the same portion, the length and width recovery of parenchyma cell was 30.96% and 5.93%, respectively. The maximum length strain of parenchymatous tissue was 0.72%. Conclusion: Image-Pro Plus could be used to analyze the cell morphology and observe the deformation directly. Parenchyma cell in the tensile layer was stretched in the longitudinal direction and compressed in the radial direction, respectively. The strain and recovery of parenchyma cell were both larger in the longitudinal direction than those in the radial direction. The parenchyma had a better elasticity in the longitudinal direction.

Key words: bamboo strips, bending, parenchyma, deformation, recovery