Learning Forum

[wancheng gao]

Hello,

I am doing nonlinear material static analysis with a few contact pairs (all nonlinear contact types) .

I saw warning and error messages at the 3rd load step (2.5mm displacement load for each load step), saying some elements were highly distorted, as shown in first figure. 

1) Then ansys bisects the substep and the analysis continued anyway. Do these messages imply the final results are unreliable even if the analysis can be finished eventually?

2) Do the force convergence figure (circled in blue) imply I may have set up too many substeps? It converged well except the two bisection moments (circled in red)  i mentioned in 3rd load step.

Appreciate any discussion or explanation!

 

[peteroznewman]

Iterations done between the last converged substep and the bisection are discarded so the error is no longer relevant. Iterations restart from the last converged substep using the smaller time step, so if there are no new warnings, then the result will be reliable.

It looks like the last step could finish in fewer iterations if you allowed a larger step size. The second last step may finish in fewer iterations but you won't be able to use the same large step size that you use in the last step, it will need to be smaller than that.

[wancheng gao]

Hello Peter,

Thank you for your reply! Now my questions are resovled.

I have seen a lot of your helpful comments on different topics. It is a pleasure to get replied by you here!

My best!

Eason