Configuring a static, linear perturbation procedure

The response in a linear analysis step is the linear perturbation response about the base state. The base state is the current state of the model at the end of the last general analysis step prior to the linear perturbation step. If the first step of an analysis is a perturbation step, the base state is determined from the initial conditions.

For more information, see Linear Perturbation Analysis Steps.

This task shows you how to:

Create or edit a static, linear perturbation procedure

  1. Display the Edit Step dialog box following the procedure outlined in Creating a step (Procedure type: Linear perturbation; Static, Linear perturbation), or Editing a step.
  2. On the Basic and Other tabbed pages, describe the step and enter equation solver preferences as described in the following procedures.

Configure a static, linear perturbation procedure

  1. In the Edit Step dialog box, display the Basic tabbed page.
  2. In the Description field, enter a short description of the analysis step. Abaqus stores the text that you enter in the output database, and the text is displayed in the state block by the Visualization module.
  3. Display the Other tabbed page.
  4. Choose an Equation Solver Method option:

    • Choose Direct to use the default direct sparse solver.

    • Choose Iterative to use the iterative linear equation solver. The iterative solver is typically most useful for blocky structures with millions of degrees of freedom. For more information, see Iterative Linear Equation Solver.

  5. Choose a Matrix storage option:

    • Choose Use solver default to allow Abaqus/Standard to decide whether a symmetric or unsymmetric matrix storage and solution scheme is needed.

    • Choose Unsymmetric to restrict Abaqus/Standard to the unsymmetric storage and solution scheme.

    • Choose Symmetric to restrict Abaqus/Standard to the symmetric storage and solution scheme.

    For more information on matrix storage, see Matrix Storage and Solution Scheme in Abaqus/Standard.

  6. Choose a Solution technique option:

    • Choose Full Newton to use Newton's method as a numerical technique for solving nonlinear equilibrium equations.

    • Choose LCP Contact to activate the linearized contact capability to solve for contact status and contact stresses. This option can be specified only within a static perturbation step with small sliding, frictionless contact.

      If you choose this technique, enter a value for the Gap distance to specify a zone within which potential contact constraints are exposed to the LCP solver and Scale factor for the initial gap distance specified in the Gap distance or the internally computed (contact) pair-wise gap distances. The default is 1.0.

  7. When you have finished configuring settings for the static, linear perturbation step, click OK to close the Edit Step dialog box.