Study on brittle fracture propagation of mixed mode

In practical engineering, mixed mode fractures of material are commonplace. So the analysis of mixed-mode crack is of both theoretical importance and practical value. Using damage mechanics and fracture mechanics, the boundary equations of fracture zone of I-II mixed mode are obtained. The new concept of the radius strain energy within fracture zone is presented. On the base of this concept, a new criterion of crack propagation is proposed. i.e. the criterion of radial minimum strain energy within fracture zone. Initiation angle of inclined crack is obtained. The wing crack is deformed, after the crack tip initiation. Dimensionless stress intensity of wing crack is analyzed with inclined angle.