Classic convergence issue 1

[soildynamics]

Does any one have any recommendation on dealing with this classic Error message that have been encountered and asked about by several guys:
"The strain increment is so large that the program will not attempt the plasticity calculation at 10 points
The plasticity/creep/connector friction algorithm did not converge at 65 points
Excessive distortion at a total of 10 integration points in solid (continuum) elements"

 

[MrMyers]

Here are a few tips - not always in the most appropriate order

1. check your unit systems are correct.
2. start with an elastic analysis and introduce one non-linear function at a time (plasticity/creep/contact/etc)- this way you can see what is causing the problems.
3. Check your mesh quality for sharp discontinuities (these can cause problems when plasticity and creep are introduced)
4. Reduce your time increment (or at least the smallest allowable time increment, if automatic)
5. De-bug your model with 'Job Diagnostics' tool to see where convergence fails
6. refine your non-linear behaviour - add hardening to plasticity
7. Check your loads and boundary conditions aren't the problem - is it load or displacement controlled? are the units and magnitudes correct?