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基于三维机织碳/碳复合材料的细观结构特征,设计平板十字形试样,在材料双轴力学性能试验机上开展了复合材料单轴、双轴加载压缩试验,对比分析了三维机织碳/碳复合材料在双轴压缩载荷下的力学行为。研究表明:三维机织碳/碳复合材料的压缩行为表现为非线性、脆性断裂;双轴载荷作用下非线性特征更为显著,压缩模量随应力的增加而增大,强度与模量相较于单轴有较大幅度增加,双轴压缩载荷作用下材料的强化效应显著;试样破坏位置并未出现在试样中心区,而是发生在试样的加载端部或十字形试样的加载分枝根部,主要表现为基体开裂、纤维断裂和层间脱粘,碳布及其层间界面剪切强度的强弱直接影响材料的压缩强度。
Based on the microstructure characteristics of the three-dimensional woven carbon / carbon composites, a flat cross-shaped specimen was designed. Uniaxial and biaxial loading compression tests were carried out on the biaxial mechanical properties testing machine. The three-dimensional woven carbon / Carbon Composites under Biaxial Compressive Load. The results show that the compressive behavior of the three-dimensional woven carbon / carbon composites shows nonlinear and brittle fracture, the nonlinear characteristics are more obvious under the biaxial load, the compressive modulus increases with the increase of the stress, and the strength and modulus phase Compared with the uniaxial, the strengthening effect of the material under the biaxial compressive load is significant. The failure position of the specimen does not appear in the central area of the specimen, but occurs at the loading end of the specimen or the cross-shaped specimen The root of loading branches is mainly manifested as matrix cracking, fiber breakage and delamination between layers. The strength of the interfacial shear strength of the carbon cloth and its interlayer directly affects the compressive strength of the material.