脆性材料复合裂纹断裂判据研究

研究了混凝土等拉压强度不等的脆性材料在平面应力和平面应变情况下裂纹附近的塑性区的范围，并给出了相应的表达式；运用在一定外力作用下物体内等效应力作为断裂判据，推测含复合裂纹的脆性材料的裂纹扩展时的临界条件相扩展方向，计算了试件在6个不同裂纹角时断裂角的大小，其结果与最大周向正应力理论判据、最小应变能密度理论判据及实验结果比较，说明用最小等效应力作为含复合裂纹的脆性材料的裂纹断裂判据是可行的．

Fracture Criterion of Brittle Material with Compound Crack

The plastic zone about the fracture of brittle material such as concrete with different compressive and tension strength is studied under plane stress and plane strain, and the equation is given. As the fracture criterion, the equivalent stress is used to infer the critical condition and the angle of crack expansion compound. The angle of crack expansion is calculated about six specimens having different crack angles. The results are well tally with the other theories and the measured ones. It shows that it is feasible to use the least equivalent stress as the fracture criterion of brittle material with compound crack.