DM-Intro 14.5 WS-06 Beam and Shell Modeling

2012 ANSYS, Inc. November 20, 2012 1 Release 14.5

14. 5 Release

Introduction to ANSYS DesignModeler

Workshop 6 Beam and Shell Modeling


Goals:

Import external geometry containing line bodies Create a line body from 3D Curve Use symmetry tool to add components Choose a beam cross section to be used and assign it to the

line body

Create a surface model representing the panel Ensuring the conformal mesh between multiple bodies using

multibody part

Beam and Shell Modeling


Launching Design Modeler First start Workbench

Go to Project Page Component Systems Geometry

1. Double click on Geometry Tab

2. Click Right Mouse Button (RMB) on Geometry template then click on New Geometry

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Unit Selection

DM starts with a prompt to select desired length unit. Select Foot and click OK.


Importing External Geometry File Import external geometry file

[Main Menu] File Import External Geometry File

1. Select The file role-cage.igs from the Input Files folder.

2. Set Operation type as Add Frozen

3. As the igs file contains line bodies Set Process Line Bodies as Yes

4. Click Generate or press F5 to import geometry

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The imported role_cage.igs file contains a partial model. We will add remaining bodies by using 3d Curve feature.

Create 3d curve [Main Menu] Concept 3D Curve

1. Set Definition From Coordinate File.

2. Browse and select the coordinate file role_cage_coordinates.txt

3. Set Operation as Add Frozen

4. Click Generate to create curve

You will find that two curves as highlighted in image are added to the model

Creating Line Bodies Using 3D Curves

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Creating Beam Model (1) To create full model we will use Mirror. The

model is symmetric across the ZXPlane. To create remaining half of the model, we will copy existing line bodies.

Create Mirror

[Main Menu] Create Body Operation

1. Select Type Mirror 2. Select 16 line bodies as

highlighted(yellow colour) in Image1(use CTRL key for multiple selection).

3. Select global ZXPlane as mirror plane. 4. Click Generate to create mirror of

selected edges.

Image1

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Creating Beam Model (2) Add line bodies, connecting mirrored line

bodies and imported line bodies.

[Main Menu] Concept Line From Points

1. Right Click in graphics area to access advanced option for selecting points

Select Point Pairs option.

2. Select 5 pairs of points by sequence as marked in Image1

3. Set Operation Type as Add Frozen 4. Generate to create line bodies

This will create a beam model of Role-Cage.

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Image1

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Uniting Line Bodies (1) Unite line bodies

There are many line bodies in model. For simplification we will unite them according to the cross sections, that we will be specifying them in later stage.

[Main Menu] Create Boolean 1. Select multiple edges as shown

highlighted in Image1(yellow colour, hold Ctrl key for multiple selection)

2. Click Apply to confirm selection.

3. Click Generate to create boolean.

Image1

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Uniting Line Bodies (2)

Similarly merge rest of the line bodies as shown highlighted in Image1.

After unite operation we can see only two line bodies in Tree Outline

Image1


Creating Surface Bodies (1) Create Surface from Edges

[Main Menu] Concept Surfaces from Edges

1. Select 12 line bodies as marked in Image1(hold Ctrl key for multiple selection)

2. Click Apply to confirm selection 3. Specify thickness for the surface

body as 0.01ft

4. Generate to create surfaces We can use only one operation

to create multiple surfaces.

We just need to take care that all the lines selected form only closed loops from which face can be created.

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Image1


Creating Surface Bodies (2)

Similarly create surfaces using rest of the line bodies.

Specify the thickness for all surfaces as 0.01ft

Finally we will have 5 surface bodies in model see Tree outline

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Adding Cross Sections

Add cross sections

[Main Menu] Concept Cross Section Circular Tube

Add two cross sections

1. CircularTube1 Specify inner and outer radius as 0.025 ft and 0.03 ft respectively as shown in Image1

2. CircularTube2 Specify inner and outer radius as 0.022 ft and 0.025 ft respectively as shown in Image2

Image1 Image2


Assigning Cross Sections (1)

After adding two cross sections we need to assign those to the line bodies in model

1. Select line body from list of entities

2. Go to details of the selected body and select cross section from available dropdown list of cross sections

3. Assign CircularTube1 cross section to line bodies as shown in Image1 and for CircularTube2 refer Image2.

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Image1


Assigning Cross Sections (2)

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Displaying Cross Section Solids

After assigning cross sections to the line bodies, the default display shows the line body with its cross section alignment . We can also display the beam with the cross section displayed as a solid.

[Main Menu] View Cross Sections Solids


Multibody Part (1) The final modeling operation is

to place all the bodies into a single part (multi-body part).

We must do this to insure that, when model will be meshed, each boundary recognizes its neighbor resulting in a continuous mesh.

1. Set the Selection Filter to Bodies.

2. In the graphics window click right mouse button and choose Select All

3. With all bodies selected, again right click in the graphics window and choose Form New Part.

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Multibody Part (2)

Notice the Tree Outline it shows a single part which contains 7 bodies.

Before Creating

Multibody part

After Creating

Multibody part


Mesh of Multibody Part Shown here we have moved to a MECHANICAL environment in Workbench and meshed the

geometry.

By grouping all bodies into a common (single) part, nodal connectivity is insured.


This completes the workshop From the main menu select File Close DesignModeler

Workbench will save any application data

From the Workbench Project Page use the file menu and save the project as DMWS6.wbpj to your working folder

Saving the Project


Appendix I Coordinate File for 3D Curve

A coordinate file must be a simple text file in the following format:

After a pound sign (#), everything else on that line is considered a comment and is ignored.

Empty lines are ignored. Data consists of five fields, all on one line, separated by spaces and/or tabs:

Group number (integer)

Point number (integer)

X coordinate

Y coordinate

Z coordinate

A data line with the same Group number and Sequence number as a previous data line is an error. A data line cannot contain the same Group number and Sequence number as a previous data line.

For a closed curve, the point number of the last line should be 0. In this case, the coordinate fields are ignored.


Appendix I Coordinate File for 3D curve


Managing External Files

The Workbench project file structure provides a directory named user_files which may be used to store CAD, or any other files you wish to associate with the project.

If you have used imported geometry in your Workbench project and subsequently intend to transfer the project to another computer you can move or place a copy of the required files in the user_files folder.

Appendix II

Example Project Directory Containing

User Files


Managing External Files (Continued)

When the project is reopened Workbench will prompt you to locate the file.

From the View Menu, select Files.

Right click on the relevant file in the list and select Repair filename.xxx.

Browse to the file in the user_files folder.

The new path will be saved with the project.

Appendix II

Documents

DM-Intro 14.5 WS-06 Beam and Shell Modeling