复杂应力条件下脆性材料的受拉破坏准则

根据脆性材料微粒对之间距离超过特定距离而破坏的微观机理,结合宏细观试验结果指出的绝大多数的破坏颗粒对的方向与σ1的方向之间的夹角都大于0°这一事实,导出了新的脆性材料张破坏准则: σ1 ασ2 βσ3≤σ],式中系数β与材料的优势角θ(破坏颗粒对的方向与σ1的方向之间的夹角的某种平均) 和泊松比μ有关．同时还指出了经典强度理论由于没有考虑优势角从而导致了它们与宏观实验结果不符．实验结果表明,在张破坏条件下此准则比经典的准则有更高的精度．

DISCUSSION ON TENSILE FAILURE CRITERION OF BRITTLE MATERIAL UNDER COMPLEX STRESS STATE

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.