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… Solver Output Overview5) As the nonlinear solution progresses, the equilibrium iteration information is shown at the bottom (sample below)
Note that for each equilibrium iteration, the residual forces (FORCE CONVERGENCE VALUE) must be lower than the CRITERION
Ideally, the residual or out-of-balance forces should be zero for a system to be in equilibrium. However, because of machine precision and practical concerns, Simulation determines a value small enough to result in negligible error. This value is the CRITERION, and the FORCE CONVERGENCE VALUE must be smaller than the CRITERION for the substep to be converged.
In the example below, after 3 equilibrium iterations, the residual forces are lower than the criterion, so the solution is converged.
Informative messages (such as convergence or bisection) are noted with “>>>” and “<<<“ in the output.