Introduction to ANSYS Mechanical (2D)

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Introduction to ANSYS Introduction to ANSYSMechanical

Transcript of Introduction to ANSYS Mechanical (2D)

Workshop 4.2 2D Structural Analysis y

Introduction to ANSYS MechanicalANSYS, Inc. Proprietary 2010 ANSYS, Inc. All rights reserved.

WS4.2-1

Release 12.1 January 2010

WS4.2: 2D Structural Analysis

Workshop 4.2 - Goals

Workshop Supplement

Workshop 4.2 consists of a 2 part assembly representing a pressure cap and retaining flange (full model shown below). We will solve it as a 2D axisymmetric model (shown on next page).

Pressure Cap p

Retaining Ri R t i i Ring

Full Model

ANSYS, Inc. Proprietary 2010 ANSYS, Inc. All rights reserved.

WS4.2-2

Release 12.1 January 2010

WS4.2: 2D Structural Analysis

Workshop 4.2 Assumptions 2D axisymmetric model assumptions:

Workshop Supplement

The retaining ring is fixed at its mounting holes. The contact region between the parts is frictionless. The base of the pressure cap is constrained using a compression only support. Note: due to the presence of the bolt holes the structure is not truly axisymmetric.

Pressure Cap

Retaining RingANSYS, Inc. Proprietary 2010 ANSYS, Inc. All rights reserved.

WS4.2-3

Release 12.1 January 2010

WS4.2: 2D Structural Analysis

. . . Workshop 4.2 Project Schematic Open the Project page. From the Units menu verify: Project units are set to Metric (kg, mm, s, C, mA, mV). Metric Display Values in Project Units is checked (on).

Workshop Supplement

ANSYS, Inc. Proprietary 2010 ANSYS, Inc. All rights reserved.

WS4.2-4

Release 12.1 January 2010

WS4.2: 2D Structural Analysis

Workshop 4.2 Project Schematic1. Double click Static Structural analysis type to add a new system. 1

Workshop Supplement

2. RMB the Geometry cell and request Properties.

2

ANSYS, Inc. Proprietary 2010 ANSYS, Inc. All rights reserved.

WS4.2-5

Release 12.1 January 2010

WS4.2: 2D Structural Analysis

Workshop 4.2 - Project Schematic3. In the Analysis Type field specify 2D. Once this setting is made the properties window may be closed if desired.

Workshop Supplement

Note this setting indicates the y model to be analyzed is not a full 3D model but represents a symmetry section. It is important that this is set prior to importing geometry as this setting cannot be changed after the import.WS4.2-6

3

ANSYS, Inc. Proprietary 2010 ANSYS, Inc. All rights reserved.

Release 12.1 January 2010

WS4.2: 2D Structural Analysis

Workshop 4.2 - Project Schematic4. Double click the Engineering Data cell to add material properties. 4

Workshop Supplement

5. With the General Materials library highlighted choose the + next to Stainless Steel to add the material to Stainless Steel the project. 6. 6 Return to Project. Project 6 5ANSYS, Inc. Proprietary 2010 ANSYS, Inc. All rights reserved.

WS4.2-7

Release 12.1 January 2010

WS4.2: 2D Structural Analysis

Workshop 4.2 Geometry Setup7. From the Geometry cell, RMB > Import Geometry and browse to: Axisym_pressure_2D_12.stp. 7

Workshop Supplement

8. Double click the Model cell to start Mechanical. 8

ANSYS, Inc. Proprietary 2010 ANSYS, Inc. All rights reserved.

WS4.2-8

Release 12.1 January 2010

WS4.2: 2D Structural Analysis

Workshop 4.2 Preprocessing9. Set the working unit system: Units > Metric (mm, kg, N, s, mV, mA).

Workshop Supplement

9

10. Change part behavior to Axisymmetric:a. Highlight the Geometry branch b. Change the 2D Behavior under the Details of b Ch h B h i d h D il f Geometry to Axisymmetric

a.

Rename the Parts: Part 1: RMB > Rename to Retaining Ring. Part 2: RMB > Rename to Pressure Cap. p

b.

ANSYS, Inc. Proprietary 2010 ANSYS, Inc. All rights reserved.

WS4.2-9

Release 12.1 January 2010

WS4.2: 2D Structural Analysis

Workshop 4.2 Preprocessing11. Change the material assigned to the Pressure Cap:a. Highlight Pressure Cap b. Under the D t il f P b U d th Details of Pressure Cap C Choose Material > Assignment = Stainless Steel.

Workshop Supplement

11a.

11b.

12. Modify contact behavior:a. In the Details of Contact Region, change the Type to Frictionless g yp

12a.ANSYS, Inc. Proprietary 2010 ANSYS, Inc. All rights reserved.

WS4.2-10

Release 12.1 January 2010

WS4.2: 2D Structural Analysis

Workshop 4.2 Contact13. Generate the Mesh:a. RMB the Mesh branch and choose Generate Mesh.

Workshop Supplement

a.

ANSYS, Inc. Proprietary 2010 ANSYS, Inc. All rights reserved.

WS4.2-11

Release 12.1 January 2010

WS4.2: 2D Structural Analysis

Workshop 4.2 Environment14. Apply Loads on the model (make sure the Static Structural branch is highlighted):a. Select the 4 inside edges (shown in dashed black lines) of the Pressure Cap . Hint : select one of the edges and use extend to limits

Workshop Supplement

b. RMB > Insert > Pressure. c. Set the pressure magnitude = 0.1 MPa.

a.

b.

c. cANSYS, Inc. Proprietary 2010 ANSYS, Inc. All rights reserved.

WS4.2-12

Release 12.1 January 2010

WS4.2: 2D Structural Analysis

Workshop 4.2 Environment15. Apply Supports to the model:a. Highlight the bottom edge of the pressure cap g g g p p (shown in black dashed lines). b. RMB > Insert > Compression Only Support.

Workshop Supplement

b.

a.ANSYS, Inc. Proprietary 2010 ANSYS, Inc. All rights reserved. Release 12.1 January 2010

WS4.2-13

WS4.2: 2D Structural Analysis

Workshop 4.2 Environment

Workshop Supplement

c. Select the middle line on the top of the retaining ring (shown in black dashed lines). d. RMB > Insert > Fixed Support. Note : Remember, the axisymmetric assumption here is that the retaining ring is a continuous solid.Actually there are bolt holes around its circumference. For this reason, when the model was created in DesignModeler this separate line was intentionally created to provide a location to add our support.

d. c.

ANSYS, Inc. Proprietary 2010 ANSYS, Inc. All rights reserved.

WS4.2-14

Release 12.1 January 2010

WS4.2: 2D Structural Analysis

Workshop 4.2 Solution Solve the model. Notes on axisymmetry :

Workshop Supplement

Notice that the model lies completely in +X space with the Y axis as the axis of revolution. This is required for axisymmetry. Axisymmetry assumes that the model is a complete 360 degree model. For this reason no constraints in the X direction are required The portion of the pressure load acting in the +X direction is assumed to required. be offset by an equal portion in the X direction.

View any warning messages/errors :a. Errors/warning messages are displayed in the Messages tab at the bottom of the graphics screen. b. b Double click on the message to view it Click OK to close the warning window it. window. Note : Note: due to the fact that the pressure cap is constrained using frictionless contact and a compression only support, weak springs are added to prevent rigid body motion

ANSYS, Inc. Proprietary 2010 ANSYS, Inc. All rights reserved.

WS4.2-15

Release 12.1 January 2010

WS4.2: 2D Structural Analysis

Workshop 4.2 Postprocessing Insert Results into the Solution branch:

Workshop Supplement

Highlight the Solution branch, RMB and insert Stress > Equivalent (vonMises) Highlight the Solution branch, RMB and Insert> Deformation > Total Switch to body select mode, select the pressure cap and repeat steps (a.) and (b.) Note the l t t N t : th last two results are now scoped to the pressure cap. This will allow us t i l t it lt d t th Thi ill ll to isolate its response.

Solve

ANSYS, Inc. Proprietary 2010 ANSYS, Inc. All rights reserved.

WS4.2-16

Release 12.1 January 2010

WS4.2: 2D Structural Analysis

Workshop 4.2 Postprocessing

Workshop Supplement

Highlight each of the result objects to inspect the results.

Equivalent Stress on all bodies

Total Deformation on Pressure Cap

ANSYS, Inc. Proprietary 2010 ANSYS, Inc. All rights reserved.

WS4.2-17

Release 12.1 January 2010

WS4.2: 2D Structural Analysis

Workshop 4.2 Postprocessing

Workshop Supplement

View Solution time by highlighting the Solution Information branch:The graphics window will change to the Worksheet view. Scroll to the bottom of the solution information and note the Elapsed Time (this will vary b machine). by hi ) Note, CP time represents the sum for all processors used. In multiprocessor machines it will sometimes exceed elapsed time.

ANSYS, Inc. Proprietary 2010 ANSYS, Inc. All rights reserved.

WS4.2-18

Release 12.1 January 2010

WS4.2: 2D Structural Analysis

. . . Workshop 4.2 Comparison 2D Elapsed Time = 9.0 seconds. 3D Elapsed Time = 41.0 seconds.

Workshop Supplement

Solution time comparison using refined 3D symmetry mesh:

ANSYS, Inc. Proprietary 2010 ANSYS, Inc. All rights reserved.

WS4.2-19

Release 12.1 January 2010