三维编织C_f/SiC复合材料的拉伸破坏行为

TENSILE DAMAGE BEHAVIOR OF THREE-DIMENSIONAL BRAIDED C_f/SiC COMPOSITES

通过三维编织碳纤维(carbon fiber, Cf)/SiC复合材料样品单向拉伸以及单向拉伸加卸载实验,结合样品断口观察,从宏观上分析了三维编织Cf/SiC复合材料单向拉伸时的力学响应,为进一步描述三维编织 Cf/SiC复合材料力学行为奠定了实验基础。实验结果表明:三维编织Cf/SiC复合材料单向拉伸时,卸载模量衰减与应力呈线性关系,残余应变的增加与应力呈二次函数关系。微裂纹主要在编织节点处萌生,沿纤维束界面扩展,最终在编织节点处汇合,导致样品发生破坏。

The macro-mechanical behavior of 3D braided carbon fiber(Cf)/SiC under tensile loading was characterized based on tensile tests. A damage evolution model was proposed according to the test results and fracture graph. Test results show that linear relationship between unload module and unload stress, the residual strain can be expressed as a second order function of tensile stress. Microcracks mainly initiate near the braid node and develop along the interface between fiber bundles and matrix, till they converge on braid node, which leads to the breaks of specimen.