Adams Advanced Package > Adams Durability > Performing Stress Recovery > Stress on Flexible Bodies

Stress on Flexible Bodies

Recovering Stresses on Flexible Bodies

In order for Adams Durability to compute stresses on a flexible body, the flexible body in your model must contain FEA stress mode information in its modal neutral file (MNF). For more information on including stress mode shapes during MNF generation, see the Adams Flex online help.

You can also compute strains on a flexible body if its MNF contains strain mode information from FEA.

Computing Stresses or Strains

You can use Adams Durability to calculate nodal stress or strain values. These values can be used to generate x-y plot displays. When you compute nodal plots, the directions x, y, and z are with respect to the flexible bodies' local-body-reference-frame (the FEA package's global coordinate system).

To compute stresses or strains:

1. From the Durability menu, select Nodal Plots.

The Compute Nodal Plot dialog box appears.

2. In the Analysis text box, enter the name of a previously run analysis. Tips on Entering Object Names in Text Boxes.

3. In the Flexible Body text box, enter the name of the flexible body.

4. In the Node to Add to List text box, enter one or more nodes on which to calculate stresses.

You can right-click in the text box, and select Pick Flexbody Node. Then, select a node by clicking on a position in the model. As you pick the nodes individually, the Selected Nodes List text box accumulates a list of all selected nodes.

5. Select stress or strain.

6. Select the values desired, as necessary.

7. Select OK.

8. Adams Durability stores the stress or strain components in a flexible body result set for the specified analysis. It adds the following field to the Adams View database for the flexible body being analyzed:

FBname_STRESS.NodeID_Value (for stress components)

FBname_STRAIN.NodeID_Value (for strain components)

where:

FBname is the name of your flexible body

NodeID is the node whose stress or strain you are calculating

_Value is the value of stress or strain you're calculating

You can also print these values to a text file.

Displaying Stress or Strain Contours

You can use Adams PostProcessor to display stress or strain as a color contour map on the flexible body. Adams Durability automatically computes a value at each node of the flexible body.

To display stress or strain contours:

1. Load your animation in the current Adams PostProcessor window.

2. Select the Contours tab.

3. Specify a stress or strain value in the Plot Type menu.

Adams PostProcessor computes the stress or strain information. This may take a while depending on the size of your flexible body and simulation. Once completed, Adams PostProcessor displays a contour legend.

4. Select the Play tool.

Adams PostProcessor displays the contours according to the color map on the legend.

Plotting Stresses or Strains

To plot the results of your nodal stress or strain computation:

1. Open Adams PostProcessor.

2. Load your plot.

3. Set Source to Results set.

4. From the Simulation list, select the analysis run that you entered in Computing Stresses or Strains.

5. Select the FBname_STRESS or FBname_STRAIN result set.

6. From the Component text box, select the node and value you previously identified.

7. Select Add Curves or Surf.

Adams Postprocessor plots the nodal stresses or strains.

Visualizing Hot Spots

Hot spots are locations of high stress or strain on a flexible body object. You can easily locate and view hot-spot information during animation displays in the Adams PostProcessor. When the Adams Durability plugin is loaded, a Hot Spots tab is available on the Adams PostProcessor dashboard for Animation displays. This tab allows you to define the hot spots and control their display.

Hot-spot information is derived from the data that is generated and cached for a flexible body during contour animations. This allows the display and control of hot-spot information to be completely interactive.

Hot spot visualization is currently supported for durability-type contours, such as stress, strain, or fatigue. Deformations are not supported.

To display hot spots:

1. Load your animation in the Adams PostProcessor window.

2. Load the Adams Durability plugin if it is not already loaded.

3. Select the Contours tab.

4. Specify a stress or strain value in the Plot Type menu.

5. Select the Hot Spots tab, and then select Display Hotspots.

6. Make other selections as described in Animation Dashboard - Hot Spots.

7. Select the Play tool.

Adams PostProcessor displays the animation with a cross hair and option label at the location of each hot spot.