6.10. Distributed Mass

You can use this feature to distribute additional mass across the faces or edges of the flexible parts in your model. Using this feature, you can idealize the inertial effects from the bodies/entities that are evenly spread across the surfaces of your model, for example, mass contribution from paint, external equipment, a large number of small objects spaced evenly across the surfaces, etc.

To define a Distributed Mass:

  1. Select the Geometry object (or a child object).

  2. You can then add a Distributed Mass object by:

    • Selecting the Distributed Mass option from the Mass group on the Geometry Context tab.

      or...

    • Right-clicking the mouse button and selecting Insert>Distributed Mass.

      or...

    • Selecting the desired geometry in the Geometry window, right-clicking the mouse, and then selecting Insert>Distributed Mass.

  3. Specify the Scoping Method property as either Geometry Selection or Named Selection. Based on the selection made in this step, select a:

    • Geometry (faces and edges only) and click Apply in the Details view for the Geometry property.

      or...

    • Face-based or edge-based user-defined named selection from the drop-down list of the Named Selection property.

  4. Specify the Mass Type as either Total Mass or Mass per Unit Area. Based on this selection, enter a value for Total Mass or Mass per Unit Area.

See the Distributed Mass object reference page for additional information about the properties of this feature.

Limitations

Note the following limitations for the Distributed Mass feature:

  • Only applied in 3D analyses.

  • Only scoped to faces or edges of bodies whose Stiffness Behavior is set as Flexible.

  • Only used in structural analyses (Static Structural Analysis, Transient Structural Analysis, Transient Structural Analysis Using Linked Modal Analysis System, and Linear Dynamic Analysis).

  • If you apply a Distributed Mass to bodies that are also part of mesh connections, like a Node Merge Group or connect mesh control combined with PrimeMesh mesh control method, that merge nodes, the application does not account for the merged entities but instead distributes the mass across all the scoped entities associated with the specified Distributed Mass. In cases where possible, you can overcome this limitation by applying a Distributed Mass on only one of the merged entities if they are identical. For example, if two bodies have identical interface faces (edges for 2D) and the Node Merge Group or Connect mesh control etc., is used to merge the nodes on two surfaces, you can apply the Distributed Mass on only one of those two faces (edges for 2D).