20.2.4 Defining nonstructural mass

You can define nonstructural mass for a region on a part or on an assembly. For more information, see Nonstructural mass definition, Section 2.6.1 of the ABAQUS Analysis User's Manual.

To define nonstructural mass:

  1. From the main menu bar in the Property module or the Interaction module, select SpecialInertiaCreate.

  2. In the Create Inertia dialog box that appears, name the inertia, select Nonstructural mass, and click Continue.

  3. Select the region for which you want to define nonstructural mass using one of the following methods:

    • Select the region in the viewport. When you have finished selecting, click mouse button 2.

      If the model contains a combination of orphan mesh instances and native part instances, select one of the following from the prompt area:

      • Select Geometry to define the nonstructural mass for a native part instance or for a reference point.

      • Select Mesh to define the nonstructural mass for an orphan mesh instance.

        You can use the angle method to select a group of nodes from an orphan mesh part instance. For more information, see Using the angle method to select multiple objects, Section 6.2.3.

    • To select from a list of existing sets, do the following:

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

    The Edit Inertia dialog box appears. The region to which you are applying the nonstructural mass is highlighted in the viewport.

  4. Choose the Units that you will use to specify the nonstructural mass magnitude. The available types depend on the type of region that you selected.

    • Select Total Mass to specify the magnitude in the form of a total mass value.

    • Select Mass per Volume to specify the magnitude in the form of mass per unit volume.

    • Select Mass per Area to specify the magnitude in the form of mass per unit area.

    • Select Mass per Length to specify the magnitude in the form of mass per unit length.

  5. Enter the nonstructural mass magnitude in the Magnitude field in the units you chose in the previous step.

  6. If you specify the mass in the form of a total mass value and the region as a set, you can choose the Distribution method for distributing the mass over the region.

    • Select Mass Proportional to distribute the total mass among the members of the set in proportion to the structural mass. The underlying structural density is scaled uniformly over the region; hence, the center of mass is not altered.

    • Select Volume Proportional to distribute the total mass among the members of the set in proportion to the volume in the initial configuration. A uniform value is added to the underlying structural density over the region; hence, if the region has a nonuniform structural density, its center of mass may be altered.

  7. Click OK to save your data and to close the dialog box.

    Symbols appear in the viewport that represent the nonstructural mass that you just created.


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