Abstract:The solution of surface displacement of an elliptical crack under compressive-shear loading was obtained by using the complexfunction method. The closing mode was established by analyzing the geometrical condition of closing crack, and the corresponding critical stress wassolved. The result corrects the traditional viewpoint, in which there exist only open or close states for an elliptical crack, and points out that the local closingis also one of crack states. Based on them, the effect of the closed crack on stress intensity factor was discussed in detail, and its rational formulae are put forward.

Key words:  elliptical crack; compressive loading; closing