37.5 Creating springs and dashpots connecting points to ground

In an Abaqus/Standard analysis you can define springs and dashpots that connect points to ground and exhibit the same linear behavior independent of field variables. For more information, see Springs, Section 32.1.1 of the Abaqus Analysis User's Guide, and Dashpots, Section 32.2.1 of the Abaqus Analysis User's Guide.

You can obtain history data of stress and strain from a spring/dashpot by using the history output request editor in the Step module. In the Domain section of the editor, select Springs/Dashpots and choose the desired spring/dashpot from the menu that appears. For more information, see Creating an output request, Section 14.12.1.

To create springs and dashpots that connect points to ground:

  1. From the main menu bar in the Property module or the Interaction module, select SpecialSprings/DashpotsCreate.

  2. In the Create Springs/Dashpots dialog box that appears, name the springs/dashpots, select Connect points to ground, and click Continue.

  3. Select the points to connect to ground using one of the following methods:

    • Select the points in the viewport. (For more information, see Chapter 6, Selecting objects within the viewport.”)

      Tip:  The Select the Entity Closest to the Screen tool in the Selection toolbar is toggled off by default. If you make an ambiguous selection, Abaqus/CAE highlights the point and displays a description of the point in the lower left corner of the viewport. Use the Next and Previous buttons to cycle through the possible selections, and click OK to confirm your selection.

      If the model contains a combination of geometry and mesh components, select one of the following from the prompt area:

      • Select Geometry to define the spring/dashpot for geometry or for a reference point.

      • Select Mesh to define the spring/dashpot for a mesh.

    • 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 Springs/Dashpots dialog box appears.

  4. In the Direction portion of the dialog box, do the following:

    • Click the arrow next to the Degree of freedom field, and select the degree of freedom with which the springs/dashpots are associated.

    • The global coordinate system determines the default spring/dashpot orientations. To specify an orientation for the springs/dashpots, click . Specify the orientation for the springs/dashpots using one of the following methods:

      • Click Datum CSYS List from the prompt area to select a name from a list of datum coordinate systems.

      • Select a datum coordinate system in the viewport.

      • Click Use Global CSYS from the prompt area to use the global coordinate system.

      Abaqus/CAE displays the local coordinate system specified for springs/dashpots in the viewport.

  5. In the Property portion of the dialog box, check the appropriate box to include:

    • Spring stiffness. Enter the force per relative displacement for springs.

    • Dashpot coefficient. Enter the force per relative velocity for dashpots.

    If you define both spring and dashpot behaviors, they act in parallel.

  6. Click OK to create the springs/dashpots and to close the Edit Springs/Dashpots dialog box.

    Symbols appear in the viewport that represent the springs/dashpots that you just created.


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