XFEM for crack propagation

Hi 

I am new in Abaqus XFEM and I am stuck at geting a crack propagation in XFEM ,working for my Master thesis, the crack doesnt propagate. In some examples its gets opened/widened, but its not propgating.

Can any one please advise me on this or help me with simple input file for checking.

I have attached a input file of mine , it owuld be of great help if someone could have alook and advise.

Thanking in advance

Thanks

Bijin

bijinvj@gmail.com