You can now solve the analysis the same as you would for any nonlinear analysis. Keep the following points in mind:
Always check the real constant sets which are related to contact pairs and check the constraint conditions on the target surfaces. Any previous "trial runs" could have changed the settings.
Always check the target surface contact status in the beginning of the analysis. If you detect any unexpected gap (or no contact) or overestimated penetration, abort the analysis and then check your geometric model. You can issue the CNCHECK command to verify the initial contact status.
Note: Initial contact results obtained and listed from CNCHECK,DETAIL, CNCHECK,POST, and the actual solution may not be always consistent with each other. The discrepancy is mainly due to applied boundary conditions and solution options. Contact results from CNCHECK,POST are, in general, closer to what the solution will provide than those from CNCHECK,DETAIL.
If your model is experiencing convergence difficulties due to contact, use the NLHIST command as a debugging tool to monitor contact information during the solution. Before starting the solution, issue NLHIST to specify the pair-based contact items (such as contact penetration or gap, contact normal stiffness, etc.) to be tracked. The resulting data are written to a file named Jobname.nlh.
You can also use NLHIST to set parameters to automatically terminate the analysis when a desired value for a contact result item has been reached. For example, the program can automatically terminate the analysis when the contact pressure falls below a critical value.
NLDIAG,CONT is another command that can be used to monitor contact information. When turned on, this feature tracks the same contact information available through NLHIST for all defined contact pairs according to the specified writing frequency (each iteration, substep, or load step). The resulting output is stored in a text file named Jobname.cnd.
By default, contact pair output quantities are written to the output file (Jobname.out) or to the screen, as specified by the /OUTPUT command. You can redirect contact pair output to a text file named Jobname.cnm by issuing the command CNTR,OUT,YES before the solution begins.
Always check your results carefully using standard engineering guidelines.
See Solve the Analysis in the Structural Analysis Guide.
If you are restarting a contact analysis, follow the normal restart procedures as discussed in Restarting an Analysis in the Basic Analysis Guide. However, be aware that the constraint conditions of target surfaces may have been set internally. Verify the constraints carefully before restarting an analysis. Only the real constants FKN, FTOLN, PINB, and FKOP can be changed, and they can only be changed at the point of restart or at the beginning of a new load step.