2D-Cf/SiC复合材料缺口试件拉伸力学行为研究

摘要

通过对V型、半圆型和细线型双边缺口2D-Cf/SiC复合材料试件进行拉伸实验,研究了不同形状缺口对试件拉伸力学行为的影响.通过引伸计获得了拉伸过程中缺口段材料整体拉伸变形与净截面应力之间的对应关系；通过应变片获得了缺口附近局部材料的应变数值,直观体现了缺口周围的应变集中现象；依据应变变化规律,分析了双边缺口试件的损伤失效进程.通过对比标准拉伸试件,全面分析了2D-Cf/SiC复合材料双边缺口试件拉伸净强度的主要影响因素和破坏机理；最后通过有限元模拟,得到了三种缺口试件缺口段材料的应变分布情况.结果表明:拉伸过程中缺口试件缺口段材料损伤失效进程具有明显的非同步性,净拉伸强度随缺口形状不同出现不同程度下降；有限元模拟结果与实验结果吻合较好.%The influence of notch types on tensile mechanical behavior of 2D-Cf/SiC composite laminates was studied by experimental and numerical methods.Specimens with symmetrical V shape,half round shape and hairline shape notches were tested respectively.The relationship between net stress and tensile deformation closed to the notches was obtained with extensometer.With strain gauges on the surface of notched specimens,the strain variation between notches was obtained.And strain concentration effect was also clearly expressed.In accordance with the law of strain variation,the damage evolution and failure process of the notched specimens were analyzed.By comparing results with that of standard specimens,the failure mechanism of the notched 2D-Cf/SiC composites was discussed,the main influencing factors to the tensile strength were also determined.Furthermore,by finite element analysis (FEA),the strain distribution of notched specimens was simulated.The results indicate that there exists asynchronous damage evolution and failure process on material between notches during tensile process,and the specimen's net tensile strength decreases to some extent with different notch types; the FEA results have good agreement with experimental data.