2D-C/SiC复合材料的拉伸损伤研究

Tensile Damage Behavior of 2D-C/SiC Composite

通过单调拉伸和循环加卸载试验,研究了2D-C/SiC复合材料的力学性能及损伤演化过程。结果表明,残余应变、卸载模量和应力的关系曲线与拉伸应力应变曲线具有类似的形状。基于细观力学建立了材料的损伤本构关系和强度模型,分析计算表明,残余应变主要由裂纹张开位移和裂纹间距决定,而卸载模量主要由界面脱粘率决定;材料的单轴拉伸行为主要由纵向纤维束决定,横向纤维束对材料的整体模量和强度贡献较小。理论模拟结果与试验值吻合较好。

The damage evolution and the tensile properties of 2D-C/SiC composite were investigated under monotonic and stepwise incremental loadings and unloadings.The experimental data show that the relational curves of the residual strain and unloading modulus versus the tensile stress have analogous form with the tensile stress-strain curve.Based on the micromechanics,a concise constitutive equation and a strength calculation model of the damaged material were established.The analysis reveals that the residual strain mainly depends on the crack opening displacement and the crack spacing,while the unloading modulus is significantly dependent on the interface debonding rate.Moreover,the uniaxial tensile behavior of 2D-C/SiC composite is mostly dominated by the longitudinal fiber bundles;the contributions of the transverse fiber bundles to the material’s modulus and strength are obviously small.The predictions given by the presented model are in good agreement with the experimental data.