Performing a stress analysis
When performing a stress analysis, the first solution you get is a coarse estimate of the stresses. This is useful to get a good grip on where the weaknesses of the design are located.
In order to get a more accurate estimation, you will have to refine a few times. Refinements are controlled under the Solutions tab (the far right one).
When you have more than one solution, the convergence plot will have enough values to show you a graph, but you will need at least three refinement levels in order to make an assumption on the convergence of the problem.