HV-3060: Transforming and Averaging Stresses

In this tutorial, you will learn how to:

•	Use various averaging methods for elemental stress

•	Transform your results

Tools

•	The Averaging method can be selected from the Contour panel.

hv-3060_contour_avg_mthd

Averaging of elemental results at a node refers to the average of all the element corner results passing through that node. If no corner results are available for an element, centroidal results will be used calculate the average. This option allows you to change the results from being element bound to being nodal bound. The various averaging options are Simple, Advanced, and Difference.

Exercise: Transforming and Averaging Stresses

This exercise uses the bd03bkt.op2 file as both the model and the results file.

Step 1: Contouring the model results.

1.	Load the bd03bkt.op2 file, located in the animation folder.

2.	Click the Mask panel button on the Display toolbar to enter the Mask panel.

3.	Verify that the Entities input collector is set to Elements.

4.	Click on Elements, and then select By ID.

5.	Enter the following element IDs into the text box: 108, 16, 12, 107.

hv-3060_ext_ent_selctn

Click Add

7.	Click Return.

8.	Click Mask Selected.

9.	Click on the Reverse button.

10.	Click in the graphics area and press ‘F’ on the keyboard, to fit the model to the active window.

11.	Select the Contour panel from the toolbar .

12.	For Result type, select Stress (t) and vonMises.

13.	Set Layers to Z1.

14.	Activate the Use corner data option.

Activating this option allows you to view the results at the corners of the elements obtained from the integration/gaussian points.

15.	Verify that the Averaging Method option is set to None.

16.	Verify that Resolved in is set to Analysis System.

17.	Click Apply.

transf_avg_strsses_none_avg

Observe the discontinuities in the contour around the node that is shared by all four elements.

Step 2: Averaging the elemental stresses using various averaging methods.

1.	Change the Averaging Method to Simple.

2.	Click Apply.

transf_avg_strsses_simple_avg

Note that the discontinuities around the node no longer exist, and you now are able to view the contour as bands.

Simple averaging means that tensor and vector components are extracted and the invariants are computed prior to averaging. In this example, the vonMises is computed at the corner of each element for the layer Z1 and then is averaged to the nodes.

For additional information - see the Simple averaging topic (located in the HyperView User's Guide).

3.	Change the Averaging Method to Advanced.

4.	Verify that Resolved In is set to Global System (proj: none).

5.	Click on the Projection Rule button, and turn on Projection (use projected axis as Sxx).

Click OK.

The Resolved in system automatically changes to Global System (proj: x, y).

transf_avg_strsses_advncd_avg

Advanced averaging means that tensor (or vector) results are transformed into a consistent system, and then each component is averaged separately to obtain an average tensor (or vector). In this example, the stress components xx, yy, zz, xy, yz, xz are computed at the corners and then averaged to the nodes. From this averaged value, the invariants (like vonMises) are computed. These results are more accurate with advanced averaging.

For additional information - see the Advanced averaging and Projection Rule topics (located in the HyperView User's Guide).

8.	Click the Averaging Options button to open the Averaging Options dialog.

9.	Activate the Feature angle averaging check box and leave the Feature angle set to 50.

hv-3060_averaging_options_dialog

10.	Click OK to close the window.

11.	Click Apply to contour the model.

hv-3060_graphics_area_example

12.	Click the Averaging Options button again to open the Averaging Options dialog.

13.	Uncheck the Feature angle averaging option and the click OK.

14.	Activate the Variation option and enter 80 into the percentage box.

15.	Click Apply.

transf_avg_strsses_advncd_avg_variation

The variation is the relative difference at a node, with respect to all nodes in the selected components.

The formula is described as follows:

For additional information - see the Variation Percentage Control topic (located in the HyperView User's Guide).

16.	Change the Averaging method to Difference.

17.	Click Apply.

transf_avg_strsses_difference_avg

This option displays the difference between the maximum and minimum corner results at a node. For tensor/vector components, the corresponding components from each element corner are extracted and the difference is calculated. For invariants, the corresponding invariants are computed from each element corner and then the difference is calculated.

For additional information - see the Difference topic (located in the HyperView User's Guide).