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Step 4: Specify geometry

Overview

Since we are using the 2D Spar element, we can represent each truss member by a line. A line can be created by joining two keypoints (ANSYS terminology for vertices). So we'll need three keypoints, located at A, B and C in the figure below. We'll locate the origin of the coordinate system at C and number the keypoints at A, B and C as 1, 2 and 3, respectively.

Create Keypoints

Main Menu > Preprocessor > Modeling > Create > Keypoints > In Active CS

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The keypoints will now be displayed in the Graphics window along with a triad that indicates the origin of the coordinate system (coincident with keypoint 3 in our case) and the axes.

See larger version

Check Keypoints

To check if the keypoints have been created correctly:

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You should see the keypoint disappear in the Graphics window. You can also check that the keypoint has been deleted using Utility Menu > List > Keypoints. You can then re-create the keypoint.

Save your work

Once you have successfully created the keypoints, save your work using

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Utility Menu > File > Save as Jobname. db

Create Lines from Keypoints

Main Menu > Preprocessor > Modeling > Create > Lines > Lines >In Active Coord

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Close the Lines and Create menus.

Check Lines

Take a look at the list of lines that have been created:

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Close the window listing lines.

Modifying Lines (If Necessary)

If a line doesn't look right, you can delete and re-create it. To delete a line:

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Click on the line you want to delete in the Graphics window. Click OK. This deletes the line.

Save your work

Once you have successfully created the lines, click on Toolbar > SAVE_DB to save the database.

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