基于广义最大周向应变准则的断裂特性研究

裂纹尖端应力场的非奇异性常数项(T应力)对脆性或准脆性材料的断裂特性及裂尖塑性区的形状和大小都有显著的影响.为了探究T应力对脆性或准脆性材料Ⅰ～Ⅱ复合型断裂特性的影响规律,基于先前研究中提出的计及T应力影响的广义最大周向应变准则进一步讨论了T应力、裂纹尖端的临界距离r0和泊松比y对中心裂纹圆盘试件的裂纹扩展路径以及临界...

A Study on the Fracture Characteristics Analysis Based on the Generalized Maximum Tangential Strain Criterion

The non-singular constant stress term (T-stress) around the crack tip remarkably affects the fracture characteristics of brittle or quasi-brittle materials, and it is also closely related to the shape and size of the plastic zone near the crack tip. In order to explore the influence of T-stress on the I~II mixed mode fracture characteristics of brittle or quasi-brittle materials, the generalized maximum tangential strain (GMTSN) criterion, which considers the effect of T-stress, has been proposed in our previous research. In this paper, the further study on the effects of T-stress, critical distance r₀ and Poisson's ratio ν on the crack propagation path and the fracture resistance for central cracked Brazilian disc (CCBD) specimens have been carried out according to the GMTSN criterion. Moreover, the GMTSN criterion is used to predict the test results obtained with CCBD specimens. The results indicate that the T-stress and Poisson's ratio have a remarkable influence on the mixed mode fracture resistance based on the GMTSN criterion. When compared with the traditional maximum tangential strain (MTSN) criterion, a negative T-stress in a CCBD specimen always decreases the absolute value of the fracture initiation angle; however, the value of critical stress intensity factor is increased for negative values of T-stress. Theoretical values based on the GMTSN criterion, which considers the effect of T-stress, are in very good agreement with the test results. Moreover, the GMTSN criterion provides a better prediction for pure mode II when compared with the generalized maximum tangential stress (GMTS) criterion.