Mech-Intro2_14.0_WS02_AdvNS

8/12/2019 Mech-Intro2_14.0_WS02_AdvNS

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2011 ANSYS, Inc. March 28, 20121 Release 14.0

14. 0 Release

Introduction to ANSYS

Mechanical Part 2

Workshop 2

Advanced Named Selection


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GoalsThe goal of this workshop is to use several techniques to create named selections

that will then be used to set up the boundary conditions shown below.

Two holes at one end of the model will be used to apply a fixed support.

On one of the remaining holes we will apply a radial displacement to simulate the

effect of a fastener that has been press fit into it.


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Project SchematicBegin a new Workbench session and, from the Project

page, choose Restore Archive . . . and browse to the

file WS2_Named_Selections.wbpz and Open (location

provided by instructor).

When prompted, Save using the default name in the

same location as the archive file.

From the Units menu verify:

Project units are set to Metric (kg, mm, s, C, mA, N, mV).

Display Values in Project Units is checked (on).


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. . . Project Schematic

1. From the Static Structural system double click

(or RMB > Edit) the Model cell.

2. When Mechanical opens, verify the units are

set to Metric (mm, kg, s, mV, mA). 2.

1.


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PreprocessingWhen Mechanical opens note the models orientation with respect to the

global coordinate system:

3. Expand the Coordinate Systems branch and highlight Global Coordinate

System.

3.


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. . . PreprocessingThe first named selection will be created so that the

constraints can be added, and conveniently

modified, to the geometry.

4. Highlight the cylindrical face of the hole nearest

the global coordinate system origin.

5. RMB > Create Named Selection.

4.

5.


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. . . Preprocessing

6. In the Selection dialog enter the nameFixture.

7. Choose Apply geometry items of same:.

8. Check the box Size.

9. In the tree, highlight the new named selectionFixture and note the scope of the selection

is 4 faces.

Since our goal is to apply the constraints only tothe 2 holes closest to the origin, we need to add alocation filter the worksheet.

9.

8.

7.

6.



. . . Preprocessing

In order to proceed we need to first determine thelocation of the features to be filtered. While there are

a number of ways we might accomplish this, well usethe selection information feature.

10. Highlight the cylindrical face used previously.

11. In the top menu click the box to activate SelectionInformation.

11.

10.

The summary shows the

face centroid is located at

an X coordinate of 8 mm.

Also note the radius of the

cylinder is 2.5 mm.



. . . PreprocessingIn the worksheet shows the initial selection (select by size) is represented bythe first row.

12. RMB in the worksheet and Add Row.

By inspection we can see that the centroid of both required holes must be at the same Xlocation. Instead of using that criteria directly well illustrate the use of a filter.

13. Configure the row to filter the selection based on X location in a range of 0 to 10 mm.

14. Generate.

1.1.

1.



. . . Preprocessing

15. With the filter applied verify the scope of the

selection is now 2 faces.

16. In the graphics window review the selection.

16.

15.


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. . . Preprocessing

Again, there are a number of ways we might proceed

with this step, but well create a geometry based

named selection and then convert it to a mesh based

selection.

Create a named selection where the press fit

simulation will be applied:

17. Select the cylindrical face shown here.

18. RMB > Insert > Named Selection.

19. In the tree RMB > Rename the new selection to

PressFace.

19.

18.

17.


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. . . Preprocessing

20. Highlight the Named Selections branch, RMB > Insert > Named Selection.

21. In the details for the new selection change the scoping method to

22. In the worksheet RMB > Add Row and configure to add a face namedselection, equal to PressFace.

22.

21.

20.


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. . . Preprocessing

23. In the worksheet RMB > Add Row and configure to convert to mesh nodes.

24. Generate the named selection.

25. In the tree, rename the selection to PressNodes.

25.

24.

23.


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. . . Preprocessing

26. Review the details and the graphics window and note that we now have anamed selection composed of 88 nodes associated with the desired face.

26.


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. . . PreprocessingAs stated earlier we wish to simulate a press fit by displacing the nodes in thecylinder in a radial direction. We need a local cylindrical coordinate system to use

as a reference.

27. Highlight the same face used to createthe previous named selection, RMB >Insert > Coordinate System.

28. In the new coordinate system detailschange the type to Cylindrical.

29. Rename the new coordinate systemPressSystem.

29.

28.

27.


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Environment

30. Highlight the Static Structural branch, RMB > Insert> Fixed Support.

31. In the details change the scoping method toNamed Selection.

32. From the drop down list choose the namedselection Fixture.

In the graphics window note the fixedsupport is scoped to the 2 holesclosest to the global origin.

32.

31.

30.


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. . . EnvironmentBefore proceeding with the next step (applying the

radial displacement to the nodes) it will be useful to

review the basics of FE loads (covered in MechanicalIntro Part 1).

Recall:

FE loads are applied to an FE based named selection.

The directions in which FE loads are applied, unlikeother loads, are always with respect to each nodes

individual coordinate system.

Because of this second point nodal orientations must

sometimes be modified so that the correct load

direction can be defined.


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. . . Environment

33. Highlight the Static Structural branch, RMB > Insert > Nodal Orientation.

34. In the nodal orientation details for Named Selection choose PressNodesfrom the drop down list.

35. In the detail for Coordinate System choose PressSystem (defined earlier).

35.

34.

33.


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. . . Environment

36. Highlight the Static Structural branch, RMB > Insert> FE Displacement.

37. In the FE Displacement details for Named

Selection choose PressNodes from the dropdown list.

38. Enter a value of 0.1 in the X component field.

Recall that the earlier nodal rotation was done with

respect to a local cylindrical system. For cylindricalsystems the X, Y and Z directions are interpreted as

radial (X), tangential (Y) and axial (Z) directions. 38.

37.

36.


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Postprocessing

Solve the model.

When the solution is complete various displacement plots can be used to verify

the loading. In the figure on the right a directional deformation result is

transformed into the local cylindrical system (PressSystem) defined earlier.

Total Deformation Transformed Deformation


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. . . PostprocessingA final verification can be done by plotting

the Nodal Triads associated with each node.

To create a clearer display, the coordinatedisplay was scoped only to the face where

the displacement is applied.

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