基于GMTS准则的岩石半圆盘试件断裂行为

Fracture behavior investigation of rock semi-circular specimens by generalized maximum tangential stress criterion

在传统MTS准则基础上加入T应力分量,建立广义最大周向应力准则(GMTS),并与传统的MTS准则比较,研究T应力对裂纹扩展的影响;采用GMTS准则预测不同复合型断裂裂纹的初始起裂角和断裂韧性,将预测结果与实验测试结果对比,研究T应力对裂纹扩展的影响规律。研究发现,裂纹尖端Williams级数解中高阶项,特别是常数项T应力对裂纹扩展的影响不可忽视,在Ⅱ型断裂占主导地位时,影响更为显著,因此GMTS准则对岩石复合型断裂角和断裂强度的预测结果更加精确。

Based on the traditional MTS criterion,the T stress component is added to establish the generalized maximum circumferential stress criterion,and compared with the traditional MTS criterion;the influence of T stress on crack propagation is studied.GMTS criterion is used to predict the initial fracture angle and fracture toughness of different composite fracture cracks,the prediction results are compared with the experimental results,and the influence of T stress on crack propagation is studied.The analysis confirms that high order terms in the Williams series solution for the crack-tip stress field cannot be ignored,especially the constant term T stress.the existence of T-stress at the crack tip has a significant effect on mode"dominant fracture.Therefore,the generalized maximum tangential are more reliable compared with those from traditional MTS criterion when used for predicting the fracture initiation angles and the fracture resistances for mixed mode fracture.