2D-SiC/SiC陶瓷基复合材料的拉伸本构模型研究

通过单向拉伸试验,研究了2D-SiC/SiC复合材料的应力-应变行为.结果表明,材料单向拉伸应力-应变曲线表现出明显的双线性特征,且线弹性段较长.通过试件断口照片,分析了2D-SiC/SiC复合材料单向拉伸破坏机理和损伤模式.基于对损伤过程的假设,建立了二维连续纤维增强陶瓷基复合材料的双线性本构模型,并将其应用于2D-SiC/SiC复合材料的应力-应变曲线模拟,模拟结果与试验值吻合很好.同时,分析计算表明,2D-SiC/SiC复合材料的单轴拉伸行为主要由纵向纤维柬决定,横向纤维对材料的整体模量和强度贡献很小.

Tensile Constitutive Model of 2D-SiC/SiC Ceramic Matrix Composites

The stress-strain behavior was studied based on monotonic tensile tests. It is can be seen that the monotonic tensile stress-strain curve shows apparent bilineadty, and its elastic-linear part is relatively long. The failure mechanics and damage mode were also studied through the photographs of broken specimens. A biUnear constitutive model for 2D continuous fiber-rainforced ceramic-matrix composites was proposed according to several fundamental hypotheses about damaging process. That model was applied to 2D-SiC/SiC composites. The predicted data is in good agreement with the experimental results. Moreover, the uniaxial tensile behavior of 2D-SiC/SiC composites is mostly dominated by the longitudinal fiber bundles. And the contributions of trans- verse fiber bundles to the material＇s modulus and strength are obviously small.