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Step 4: Specify geometry

We'll first create keypoints corresponding to the eight vertices of the model and then generate a volume from the keypoints. The keypoints will be created in the cylindrical coordinate system. Four of the keypoints are the vertices A,B,C and D shown in the figure of the geometry. The other four keypoints have the same r and θ as A,B,C and D but are displaced in the z-direction with respect to them.

Create Scalar Parameters

For convenience, we'll create scalar parameters for the geometric dimensions in SI units.

...

R1=44e-3
R2=R1+88e-3
Z1=65e-3
Z2=14e-3

 
Click Close.

Switch to Cylindrical Coordinate System

Utility Menu > WorkPlane > Change Active CS to > Global Cylindrical

Check that ANSYS reports the active coordinate system in the Output window :

The reference number that ANSYS uses for the cylindrical coordinate system is 1 (the Cartesian system is 0).

Save your work: Toolbar > SAVE_DB

Create Keypoints

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

When the active coordinate system is set to cylindrical, X, Y, and Z in the menus refer to the cylindrical coordinates r, θ (in degrees) and z, respectively. Remember to make this mental substitution as you enter the keypoint coordinates. Also, you can use the tab key to move the cursor to the next entry field. Don't forget to change the keypoint number as you enter the coordinates of the keypoints.

Enter the keypoint locations (think about where each one lies as you enter its coordinates):

...

Switch to the isometric view: Utility Menu > PlotCtrls > Pan, Zoom, Rotate > Iso

(Click for Larger Image)

Note the orientation of the x-y-z triad at the bottom in the isometric view. The Pan-Zoom-Rotate menu, as the name indicates, can be used to change the viewing direction, zoom in and out and rotate the model. Close this menu.

ANSYS reports "csys=1" at the top of the Graphics window, csys referring to the coordinate system. This is a quick way to check the current active coordinate system.

Create Volume

We'll next generate a volume from the 8 keypoints. The order of the keypoints should be around the bottom first and then the top.

...

Pick the 8 keypoints in the order in which they are numbered. Click OK in the pick menu.

Plot Lines

Let's take a look at the lines that ANSYS generated in the volume creation process:

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Utility Menu > PlotCtrls > Style > Background > Display Picture Background

Save Your Work

Toolbar > SAVE_DB

Go to Step 5: Mesh geometry