DISCUSSION ON TENSILE FAILURE CRITERION OF BRITTLE MATERIAL UNDER COMPLEX STRESS STATE
复杂应力条件下脆性材料的受拉破坏准则

It is indicated by macroscopical and microscopical experiments that most of the directions of failure particle pair are not consistent with the direction of the first principal stress. According to the microscopic mechanics with respect to brittle materials' tensile failure, the material will begin to decompose if the distance between pair particles exceeds their attraction distance. Based on the above facts, a new strength criterion of brittle materials' tensile failure is derived, which can be written as: $\sigma_1+\alpha \sigma_2+\beta \sigma_3\le \sigma]$, in which the coefficients are dependent on the predominant angle and Poisson's ratio. It is pointed out that the reason why the classical criteria disagree with experiments is that the predominant angle is not considered in the classical criteria. The new criterion is shown to be more accurate than the classical criteria for tensile failure of brittle materials by experiments.