基于大尺度重组竹试件各向轴压力学性能研究

Comparison Study on Parallel Bamboo Strand Lumber under Axial Compression for Different Directions Based on the Large Scale

对大尺度重组竹试件进行了3个方向轴心受压试验研究与分析,探讨了其破坏机理及所测参量之间的相互关系.竹重组材的受压破坏属于延性破坏,沿3个方向的破坏过程均经历弹性阶段、弹塑性阶段、塑性阶段和破坏阶段;但破坏阶段有所区别.试件各向受压的最终破坏形态较接近,均出现沿对角线方向的主裂缝.顺纹方向的实测抗压强度、弹性模量和泊松比值最大,离散性较大;横纹方向Ⅰ的抗压强度稍大于横纹方向Ⅱ的抗压强度,但其弹性模量和泊松比均比横纹方向Ⅱ对应的值要小.基于试验结果,给出了各个方向抗压强度、弹性模量和泊松比相互之间对应的关系.

In order to investigate the axial compression damage mechanism and the relationship between the test parameters for three directions,the experimental study on parallel bamboo strand lumber（ PBSL） based on the large scale was conducted in this paper. The axial compressive failure for the PBSL belongs to the ductile damage. Except for the different damage stage,the whole failure process for specimens along three directions are similar with each other and can be divided into four stages： elastic stage,elastic-plastic stage,plastic stage and failure stage. The final failure mode for the three directions are similar with each other which is the main crack appeared along the diagonal. With large discreteness,the compressive strength,modulus of elasticity and Poisson＇s ratio for the parallel to grain direction are biggest among three directions. The compressive strength for the perpendicular to grain direction Ⅰ is bigger than that for Ⅱwhile the modulus of elasticity and Poisson＇s ratio for direction Ⅰ is smaller than that for Ⅱ. Based on the test analysis of the results,the relationship between the compressive strength,modulus of elasticity and Poisson＇s ratio for three main directions were proposed for the PBSL under axial compression.