INTERACTION BETWEEN EDGE DISLOCATIONS AROUND THE TIP OF A CRACK

The interaction between edge dislocations around the tip of a crack ha s been analyzed analytically and numerically. It is found that when th ese dislocations are placed on a cylinder around the crack tip with th eir slip planes all passing through the tip, the slip force exerted on a dislocation by another dislocation and its images is zero regardles s of their locations on the cylinder. Inside as well as outside this c ylinder other zero-slip-force positions also exist. The results show t hat a plastic zone around a crack tip is stable.