重组竹是将竹丝束平行组坯、经高压胶合而成的一种生物质复合材料,是一种极具潜势的建筑结构材料。研究重组竹的基本力学性能和应力应变关系,是建立此类材料本构关系和进行重组竹结构非线性分析的基础。将重组竹理想化为横向各向同性复合材料,通过试验,给出了重组竹各主轴方向的单轴与各主平面的纯剪力学参数,建立了各种应力状态下的应力应变关系。结果表明,重组竹力学性能优于常用的结构用木材,且变异性较小。重组竹顺纹受拉强度约是顺纹受压强度的2倍;横纹受拉强度远远低于横纹受压强度;横切面内的剪切模量及强度远远低于另外两个方向,且横纹剪切强度是顺纹剪切强度的3倍。重组竹的应力应变关系和破坏模式与纤维参与受力程度密切相关。顺纹受拉时,拉应力完全由纤维承担,破坏表现为纤维的脆性拉断,强度最高,应力应变为完全线性关系;其他应力状态下,破坏均发生在基体或纤维-基体界面,若裂纹的扩展受到纤维限制,破坏呈渐进性,强度较低,应力应变曲线由早期的线性关系转入后期的非线性关系;当裂纹的扩展未受到纤维限制,破坏强度最低,应力应变呈线性关系。 Bamboo is a reorganization of bamboo strands parallel to the billet, the high-pressure glued together from a biomass composite material, is a very potential building materials. Studying the basic mechanical properties and stress-strain relations of reorganized bamboo is the basis of establishing the constitutive relation of such materials and carrying out the non-linear analysis of reorganized bamboo structure. The idealization of the recombinant bamboo into a transversely isotropic composite material, through the test, the pure shear mechanical parameters of the uniaxial and principal planes of each direction of the reorganized bamboo are given, and the stress-strain relationship under various stress states is established. The results showed that the mechanical properties of bamboo reorganized better than the commonly used structural wood, and less variability. Tensile strength of the reorganized bamboo lines is about twice that of the parallel compression lines; the tensile strength of the transverse stripes is much lower than that of the transverse stripes; the shear modulus and strength in the transverse section are far lower than the other two Direction, and the transverse shear strength is three times the shear strength along the grain. The stress-strain relationship and failure mode of reorganized bamboo are closely related to the degree of fiber involvement. The tensile stress is completely borne by the fiber when tensile in tension, and the failure manifests itself as the brittle pull-off of the fiber with the highest strength and complete stress-strain linearity. Under other stress conditions, the failure occurs at the matrix or the fiber-matrix interface. The damage is progressive and the strength is low. The stress-strain curve changes from the early linear relationship to the later nonlinear relationship. When the crack propagation is not restricted by fiber, the damage intensity is the lowest, and the stress-strain curve shows a linear relationship.