5 cutbacks at start of new step - cutback reason "material point calculations"

[slimjimmy]

Hi everyone,

I'm running a analysis with 4 forming steps. The model runs fine up to the 4th step. At the start of the 4th step, I get 5 cutbacks on the first increment. In Job diagnostics the cutback reason is "material point calculations". To debug, I have added in dummy 4th step with no additional constraints/interactions etc (basically the exact same as the BCs in the 3rd step) and I still get 5 cutbacks. Why can the model complete step 3 with relative ease and suddenly not be able to complete the 1st increment on the next step? Is this a rigid body motion problem and if so why was step 3 able to converge? Some more info: standard, surface to surface contact, soft contact. Let me know your thoughts. Thanks!

 

[FEA way]

If you keep the loads in this dummy step then it’s possible that with increasing load model loses convergence due to large nonlinearity (contact/plasticity/NLGEOM). Here it seems that plasticity is the reason. Try adjusting material properties and, just in case, enable automatic stabilization.