Define physical damping

To define physical (non-modal) damping, you must either add the appropriate Simcenter Nastran or MSC Nastran parameter in the solution attributes or add the appropriate elements (such as dampers or bushings) and physical properties in your FEM. When you solve the modal solution, Simcenter Nastran or MSC Nastran calculates the physical damping.

In the Simulation Navigator, in the Response Dynamics Details View, you can view the contribution percentage of physical damping in the %Phys_Hyst and %Phys_Visc columns. The Damped Frequency column shows the effect of all damping (modal and physical damping, including damping calculated through Rayleigh's Damping) on the normal mode frequency.

Example: Add damping in physical properties

These steps describe how to add a damping value to the physical properties for a CDAMP1 element.

Note:

With CDAMP2 elements, you define the damping value directly in the Mesh Associated Data dialog box for the element.

1. At the damped location in your FEM, add a CDAMP1 element (Menu→Insert→Element→Create→1D).

2. In the Simulation Navigator, expand the 1D Collectors node and select the mesh collector that contains the damper element you created.

3. Right-click the mesh collector and choose Edit.

4. In the Mesh Collector dialog box, click Edit .

5. In the PDAMP dialog box, in the Viscous Damping, Extension and Viscous Damping, Rotation boxes, enter the appropriate damping values.

6. Click OK to close the PDAMP and Mesh Collector dialog boxes.

Example: Add damping in Simcenter Nastran parameters

These steps describe how to add the PARAM, G Simcenter Nastran parameter to the solution.

1. In the Simulation Navigator, right-click the solution and choose Edit.

2. Click the Parameters tab.

3. Next to Parameters, click Create Modeling Object .

4. Expand the G-H group.

5. In the G box, type your damping value and select the Add check box.

6. Click OK to close both dialog boxes.

Enable and scale the damping

These steps describe how to enable and scale the damping ratio for a response evaluation.

1. After adding the appropriate damping information to the FEM, solve the model.

2. Create a Response Dynamics solution process.

3. In the Simulation Navigator, locate the node for your Response Dynamics solution process (indicated with the icon).

4. Under the Modal Representation node, select Normal Modes.

5. Right-click Normal Modes and choose Physical Damping Settings.

6. Select the check box for the appropriate type of damping to include from Simcenter Nastran.

7. To scale the damping calculated by Simcenter Nastran, enter an integer value in the Scale Factor boxes.

8. Click OK.

How do I

Define modal damping

Calculate viscous damping using Rayleigh's method

Learn more

Damping

Quick links

Command reference

Pre/Post video examples

Bulk Entry Descriptions

Simcenter 3D tutorials

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Define physical damping, Simcenter 3D 2021.1 Series

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