Hello,

       Currently , I am working on the fatigue crack propagation in ANSYS 12.1. Can anybody help me regarding how to get the next cracktip position?

Currently, I am referring to the paper named, “Mixed mode fracture analysis of aluminium repaired panels using composite patches” , Authors : Hossein Hosseini-Toudeshky, Bijan Mohammadi, Hamid Reza Daghayani.

According to this paper, I am using following two equations for calculating the incremental angle of crack propagation (α) :

Refer images.

But, I am confused in which direction does I have to take angle α , i.e. in anticlockwise direction or clockwise direction with respect to the X-axis of the local co-ordinate system at the crack tip? Please Help me if anybody knows about this.