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通过平纹编织碳纤维增韧碳化硅复合材料的拉伸、压缩和剪切的单向与循环加–卸载实验,分别研究了材料在拉伸载荷、压缩载荷和剪切载荷作用下的力学性能和损伤演化过程。结果表明:在压缩载荷作用下,材料的压缩性能下降很小,基体开裂,纤维界面脱粘和纤维束断裂为主要的失效机理;材料在拉伸和剪切载荷作用下,损伤演化过程有所区别。材料拉伸损伤演化经历损伤初始阶段、损伤加速阶段和损伤减缓阶段,为韧性断裂,损伤破坏主要表现为:基体开裂、横向纤维束开裂,界面层脱粘、层间剥离和纤维断裂;在剪切载荷作用下,经历损伤加速阶段和损伤减缓阶段,基体开裂、界面层脱粘和纤维断裂为主要的损伤机理,试样最后在最窄截面位置形成平断面。基于实验研究结果,采用回归分析方法,分别给出了材料在拉伸载荷和剪切载荷作用下损伤演化方程式。
Uniaxial and cyclic loading-unloading experiments of tensile, compression and shearing of plain weave carbon fiber reinforced silicon carbide composites were carried out. The mechanical properties and damage of the materials under tensile, compressive and shear loadings were studied respectively Evolutionary process. The results show that under the compressive load, the compressibility of the material decreases little, the matrix cracking, the debonding of the fiber interface and the fiber bundle breakage are the main failure mechanisms. Under the tensile and shearing loads, the damage evolution process the difference. Tensile damage evolution of the material experienced the initial stage of damage, accelerated damage stage and damage mitigation stage, as ductile fracture, damage damage mainly as follows: matrix cracking, transverse fiber bundle cracking, interfacial layer debonding, interlayer delamination and fiber breakage; Under the action of shear load, the main damage mechanism was experienced during acceleration and mitigation of damage, matrix cracking, debonding of interface layer and fiber fracture. Finally, the sample formed a flat section at the position of the narrowest cross section. Based on the experimental results, the damage evolution equations of the material under tensile and shear loads are given respectively by regression analysis.