The step-wise linearity feature allows you to disable rupture and nonlinearity for a given step and enable it later in the analysis. This can be especially useful for problems that involve contact, which can erroneously interfere with damage predictions.
*LINEARSTEPS step#
The *LINEARSTEPS keyword must be a child of the *MATERIAL keyword. The data line that follows the *LINEARSTEPS keyword is used to specify the step(s) that should display a linear response. You may specify as many steps as desired, using a comma to separate each step number.
Consider the example below, where we want to disable rupture and nonlinearity for the first two steps of a three-step analysis.
*MATERIAL, NAME=IM7_8552 *LINEARSTEPS 1,2