Nonlinear Calculation - Design Details
In the final window, you can check the course of the nonlinear calculation. The output is partitioned into two main parts.
This part lists the general specifications for the nonlinear calculation (see explanations to Figure 2.30).
The convergence behavior is an important criterion for evaluating the results. The iteration process allows conclusions to be drawn on the quality of the nonlinear calculation. In the table, you can see the break criteria of the iteration steps for each load increment. The output is displayed separately for the ultimate limit state, the Serviceability limit state, and the Fire Resistance Design.
In the majority of cases, a nonlinear calculation converges because the deviations concerning internal forces, stiffnesses, and deformations are steadily decreasing. This effect can be checked by means of the values ε1 and ε2 in successive iterations: Hence, peaks or increasing deviations (in case of stability analyses, for example) are easy to understand.
Looking at the convergence behavior, you can also see how the parameters can be influenced to control the calculation (see Chapter 2.4.9).