Crack evolution under nano indentation. Convergence problem.

[mdama]

Hello
I have modeled a 3d plate with a flat punch indenter plus a crack (xfem) with damage evolution law. (The model can be seen here (

https://www.dropbox.com/s/w6l6uuhmc182qbo/nanoin.png?dl=0).(the

behavior is linear elastic fracture)

I have defined two steps: load and unload
I want to see the crack evolves (mode II) upon loading. (

https://www.dropbox.com/s/34ukwdgu0c09klr/2.png?dl=0.

I get this error: ***ERROR: TOO MANY ATTEMPTS MADE FOR THIS INCREMENT

I have used 10000 increments.
Any suggestion for how to have a better mesh when we have crack? or how to mesh near the crack area.

I want to get load-displacement curve in the presence of a crack.

Thanks

 

[DanStro]

That error is saying that there were too many attempts, it is not saying that the number of increments that you entered is too small. Try decreasing you initial increment (and maybe min too). If it still doesn't converge you should look at your model to see if there are any errors such as a bad mesh or material definition.

There are a few places on the web that you can look to give you advice on crack propagation modeling, including a site dedicated to XFEM in abaqus, though I can't remember the exact address.