For each step in the analysis you can choose whether Abaqus will account for nonlinear effects from large displacements and deformations. If the displacements in a model due to loading are relatively small during a step, the effects may be small enough to be ignored. By default, these geometrically nonlinear effects are considered for General Static steps, Riks steps, and Explicit Dynamics steps; and these effects are not considered for all other types of steps. However, in cases where the loads on a model result in large displacements, nonlinear geometric effects can become important. The Nonlinear geometry setting for a step determines whether Abaqus will account for geometric nonlinearity in that step.

The sequence of steps and the current setting determine whether you can change the setting in a particular step. For example, if Abaqus is already accounting for geometric nonlinearity, it continues to do so in all subsequent steps and you cannot change the setting. See General and linear perturbation procedures in the Abaqus Analysis Guide for a more detailed discussion of geometric nonlinearity.

The Nonlinear geometry setting is turned on by default for General Static steps, Explicit Dynamic steps, and Riks steps and turned off by default for all other types of steps. However, if hyperelastic materials are included in the model, the Nonlinear geometry setting is also turned on by default for other step types in a Nonlinear Structural case. The sequence of steps and the current Nonlinear geometry setting determine whether you can change the Nonlinear geometry setting in a particular step. For example, if Abaqus is already accounting for geometric nonlinearity, the Nonlinear geometry setting is toggled on for all subsequent steps, and you cannot toggle it off.

See General and linear perturbation procedures in the Abaqus Analysis Guide for more information.