The conventional minimum strain energy density (SED) criterion is modified by taking into account the effect of nonsingular stress term (T⁃stress) in addition to the singular stress term. Then we use the modified SED criterion to study the effect of T⁃stress on the fracture initiation angle and the critical intensity factors of brittle mate⁃rials under mode Ⅰ, mode Ⅱ and mixed Ⅰ⁃Ⅱ mook loading conditions. The general conditions for forecasting mode Ⅰ, mode Ⅱ and mixed Ⅰ⁃Ⅱ mode fracture under various T⁃stress are provided. The forecast results are compared with some earlier experimental results. The analysis shows that the presence of T⁃stress has a significant effect on mode Ⅰ, mode Ⅱ and Ⅰ⁃Ⅱ mixed mode fracture in brittle fracture of linear elastic materials; there is a good agreement between experimental results and results forecast with the modified SED criterion.%在考虑裂纹尖端应力场常数项 T 应力的基础上对传统的最小应变能密度因子准则（minimum strain energy density criterion，SED）进行修正，应用修正的最小应变能因子准则对Ⅰ型、Ⅱ型和Ⅰ⁃Ⅱ复合型脆性断裂问题分别进行研究，分析 T 应力对裂纹扩展方向和断裂时刻应力强度因子的影响并给出不同 T 应力条件下的通用的Ⅰ型、Ⅱ型和Ⅰ⁃Ⅱ复合型裂纹扩展条件，并将预测结果与现有的试验数据进行比较。分析表明，T 应力对于Ⅰ型、Ⅱ型和Ⅰ⁃Ⅱ复合型断裂均有显著影响，考虑 T 应力的 SED 预测结果和试验结果吻合很好。
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