拉伸荷载下分支裂隙破坏机理研究

为研究拉伸荷载下分支裂隙对破坏模式的影响,保持主裂隙参数不变,改变分支裂隙倾角和长度,利用扩展有限元方法模拟了弯折裂隙的动态扩展,总结了分支裂隙参数变化对破坏模式的影响。利用ABAQUS中的轮廓积分计算了分支裂隙尖端应力强度因子,并根据最大周向应力准则计算起裂角。结果表明:拉伸荷载下分支裂隙出现三种破坏模式;分支裂隙倾角和长度均对破坏模式有一定的影响。I型应力强度因子与分支裂隙倾角关系曲线呈斜"S"型,相应II型应力强度因子曲线呈上凸型;由于分支裂隙存在非尖端破坏,利用裂隙尖端应力强度因子判断开裂应结合相应的破坏模式。

Research on failure mechanism of branch crack under tensile loading

To study the influence of the branch crack on failure modes under tensile load, the dynamic expansion of the kinked crack is simulated by extended finite element method. The impact of variation of branch crack parameters on the failure pattern is summarized by changing branch crack angles and lengths. Stress intensity factors and cracking angles of the branch crack are calculated by contour integration and the maximum circumferential stress criterion based on ABAQUS, respectively. The results show that there are three failure modes for different branch cracks presented in this study. The branch crack angle and length both have a certain influence on the failure mode. The relationship between model I stress intensity factor and branch crack angle is oblique "S" type, while for model II it is convex. Due to the non-tip damage of the branch crack, to judge whether cracking by the crack tip stress intensity factor is not fully applicable. The prediction of the crack initiation angle is only consistent with the tip damage.