脆性材料在双向应力下的断裂和失效研究

Fracture and Failure of Brittle Materials under Biaxial Stress

采用热力学方法对脆性薄片试样成功地进行了双向和单向平面拉伸试验，通过观察和记录试片中心的直通裂纹的扩展和断裂过程，测试出玻璃和陶瓷薄片的断裂韧性在双向和单向拉伸载荷时的差别．结果表明双向拉伸使裂纹阻力增强，平行于裂纹的应力对裂纹扩展有影响．该研究表明，对线弹性材料在双向载荷作用下，传统的应力强度因子准则不适用．裂纹张开的应变依赖性被证实在双向应力的断裂评价中．

Brittle thin plate with a straight-through crack under biaxial and uniaxial tension in-planewas investigated by thermomechanical method. The critical stress intensity factor under those twoloading modes was measured with disk-shaped specimens of glass and ceramics . The results showthat the crack resistance of brittle materials increases with increasing stress paxallel to the crackplane. The effects of biaxial stress reveal that the conventional criterion with the stress intensityfactor is imperfect for biaxial stress issues. It is demonstrated that the crack opening and growthis governed by the strain at the crack tip.