Modelling of Crack Propagation in ABAQUS

Hello all,

I am new to ABAQUS. And my work is to model reflective crack propagation in flexible pavements. Initially i am trying to model a crack propagation in a beam with two point loads. I have tried to use both contour integral and XFEM. I need the values of J-integral at the crack tip. When i am asking J-integral in history output ( In a model where i used XFEM), it is showing that J-inegral is available for XFEM cracks which are not stationary XFEM cracks. I don't know how to resolve this issue. Can somebody help me?

Thanks in advance

Prashanthi