Why the results of stress intensity factor can not converge

[cgriver]

Hi,
I am using Abaqus 6.7-1 to solve the plate with a hole in the center. There are two cacks at left and right of the hole. Because of symmetry problem, I did for a half. However, the SIF could not converge and so much different from the theoretical solution although the I increased the mesh. I attached the input file. I highly appreciate any your help. Thank you.

 

[corus]

Couldn't find the cracks (cacks?) in the model from the cae file alone, however if you have a crack then the stress at the tip will be infinite and it will never converge.

corus

 

[cgriver]

Thanks Corus for your message. Yes, this is the singularity in fracture mechanics (r^-0.5)but I think this is not my problem.
Anyway, to see the crack you can look at the Engineering features in Assembly section (crack was assigned as a seam).
Thanks