Creating a member size restriction

You can specify the minimum or maximum size of selected regions of your model; for example, the minimum thickness of a rib that is modified during the shape optimization. The value that you enter can be thought of as a radius. During the optimization the Optimization module restrains the thickness of a member to be twice the value that you entered (the diameter). If you enter a value for the minimum thickness, the Optimization module adjusts surface nodes such that the minimum diameter must be achieved along a normal to the surface of the model. If the structure is smaller than the specified value in certain regions, the shape optimization permits only growth until the member size in the regions areas satisfies the restriction. Conversely, if you enter a value for the maximum thickness, the Optimization module adjusts surface nodes such that a maximum diameter must be achieved along a normal to the surface of the model. If the structure is larger than the specified value in certain regions, the shape optimization permits only shrinkage until the member size in the regions areas satisfies the restriction.

Related Topics
Creating a geometric restriction in a topology or sizing optimization
Creating a geometric restriction in a shape optimization

  1. From the main menu bar, select Geometric RestrictionCreate.

    The Create Geometric Restriction dialog box appears.

    Tip: You can initiate the Create. procedure in two other ways:

    • Click Create in the Geometric Restriction Manager. (You can display the Geometric Restriction Manager by selecting Geometric RestrictionManager from the main menu bar.)

    • Click the tool in the Optimization module toolbox.

  2. From the Create Geometric Restriction dialog box that appears, enter the name of the geometric restriction.

  3. Select Member size (Shape) from the list of geometric restrictions, and click Continue.

  4. From the viewport, select the region to which the member size restriction will be applied or click Done to apply the member size restriction to the entire model.

    By default, Abaqus/CAE allows you to select all of the model. To select faces or cells, use the Selection toolbar to change the type of object that you can select to Face or Cells. For more information, see Filtering your selection based on the type of object.

    If you would rather select from a list of existing sets, do the following:

    1. Click Sets on the right side of the prompt area.

      Abaqus/CAE displays the Region Selection dialog box containing a list of available sets.

    2. Select the set of interest, and click Continue.

    Note:

    The default selection method is based on the selection method you most recently employed. To revert to the other method, click Select in Viewport or Sets on the right side of the prompt area.

  5. When you have finished selecting the geometric restriction region, click Done in the prompt area. For more information on selecting objects, see Selecting objects within the viewport.”

    The Edit Geometric Restriction dialog box appears.

  6. Do either of the following:

    • Select Minimum thickness, and enter the minimum radius of a member.

    • Select Maximum thickness, and enter the maximum radius of a member.

  7. If desired, toggle on Ignore in first design cycle (default). When the optimization starts, it assumes the selected regions already include members larger than the minimum thickness. If the regions include smaller members, the Optimization module issues a warning and tries to continue. If you toggle off Ignore in first design cycle, and the regions include smaller members, the Optimization module issues an error message and stops execution.

  8. Click OK to create the member size geometric restriction and to exit the editor.