Using the Results while solving functionality in the study step is a good practice. You can either use a stress plot, or a plot of the contact pressure. In most cases, the scale of a deformed plot should be set to 1 when monitoring contact problems. If you select Results while solving in the Segregated node, the plot is updated after each iteration, thus allowing you to monitor the convergence in detail.

For each contact pair, two global variables that can be used in probe plots are available. These are the maximum contact pressure (<phys>.Tnmax_<pair>) and the minimum gap distance (<phys>.gapmin_<pair>).

Looking at the convergence plot will give valuable information about the convergence properties. There will, as a default, be one graph per Contact node in the Model Tree, which will help you pinpoint the source of a convergence problem. You can also increase the granularity even more by changing Solver log to Detailed in the Advanced node in the solver sequence. This will give a separate convergence curve for each dependent variable.

You can also select to include information about the contact state in the solver log. To do that, select the Add contact status to solver log check box in the Advanced section of the settings for the Contact node. For each contact pair, messages like