Introduction to ANSYS Meshing Tools

Nyquist/Haghighi

ABE 601

Introduction to ANSYS Meshing Tools The objective of this example is to introduce the ANSYS tools used to control mesh density. The following is the step-by-step procedure for the meshing tutorial using the ANSYS GUI (Graphic User Interface) environment. Using the left button of the mouse, click on everything that is typed bold and type everything that is italicized below. Start ANSYS. (Go to Utility Menu) File Change Directory: select abe450 OK File Change Jobname: Meshing Tutorial Click the “New log and error files?” box OK Section 1: Creating the Geometry (Go To Main Menu) Preprocessor Element Type Add/Edit/Delete Add Structural & Solid & Quad 8 Node 82 & OK Close Element Type window Modeling Create Areas Rectangle By Dimensions (Click X1 box) 0 (Click X2 box) 15 (Click Y1 box) 0 (Click Y2 box) 10 OK (Defines a rectangle by two opposite corner points (0,0) and (10,15)) (Go To Utility Menu) PlotCtrls Numbering (Go to KP and click) OFF (then OFF will be toggled to ON) (Go to LINE and click) OFF (then OFF will be toggled to ON) OK

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Nyquist/Haghighi

ABE 601

Plot Lines

(Go To Utility Menu) File Save as Jobname.db (Check the working directory)

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Nyquist/Haghighi

ABE 601

Section 2: Meshing the Geometry (Go To Preprocessor) Meshing MeshTool (the window below will appear)

This is the SmartSizing option. To automatically mesh the geometry, check the Smart Size box and select a mesh density from 1 (Very Fine) to 10 (Very Coarse).

The Size Controls assign element sizes to areas, lines, and keypoints.

Selects the geometry (volume, area, line) to mesh. Free Mesh has no element shape restrictions and does not follow any pattern. Mapped Mesh restricts element shapes to quadrilaterals and hexahedra (bricks) and typically has a regular pattern. Use the Mesh button to mesh the entities. Use the Clear button to remove an unacceptable mesh.

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Nyquist/Haghighi

ABE 601

Types of Meshing Controls Keypoint Sizing Command The keypoint sizing command (KESIZE) controls the element size at keypoints. Different keypoints can have different KESIZEs, giving you more control over the mesh. This is useful for stress concentration regions. Entering a smaller value will create smaller elements (a more dense mesh) while entering a larger value will create larger elements (a more coarse mesh).

Click on the Keypts SET button (a picker will appear) (Pick keypoints 1 and 2) & OK (the window shown above will appear) (Click the SIZE box) 2 & OK Click on the Keypts SET button (Pick keypoints 3 and 4) & OK (Click the SIZE box) 0.5 & OK Click the Mesh button (Pick the rectangle) & OK

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Nyquist/Haghighi

ABE 601

Click the Mapped button Click the Mesh button (Pick the rectangle) & OK The following message will appear:

Click OK

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Nyquist/Haghighi

ABE 601

Click the Clear button (Click on Pick All) Click on the Keypts CLEAR button (Click on Pick All) (Go To Utility Menu) Plot Lines

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Nyquist/Haghighi

ABE 601

Line Sizing Command The line sizing command (LESIZE) controls the element size at lines. Different lines can have different LESIZEs. The element edge length (SIZE) or the number of element divisions (NDIV) can be specified. If the number of element divisions is entered, the spacing ratio can be specified (SPACE). The spacing ratio is used to bias the divisions towards one end or towards the middle. Definitions: SIZE = element edge length. NDIV = number of element divisions for a line. SPACE = the spacing ratio is used to bias the divisions towards one end or towards the middle. Note: the first division begins at the end of the line with the lower keypoint number. If a positive value is entered, SPACE is the ratio of the last division to the first division.

SPACE =

Last Division First Division

If a negative value is entered, the divisions are biased towards the middle.

SPACE =

Center Division End Division

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Nyquist/Haghighi

ABE 601

Click on the Lines SET button (a picker will appear) (Pick Line 1) & OK (the window shown above will appear) (Click the SIZE box) 1 & Apply

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Nyquist/Haghighi

ABE 601

(Pick Line 2) & OK (Delete the value from the SIZE box) (Click the NDIV box) 8 (Click the SPACE box) 3 & Apply

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Nyquist/Haghighi

ABE 601

(Pick Line 3) & OK (Click the NDIV box) 10 (Click the SPACE box) -0.3 & Apply

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Nyquist/Haghighi

ABE 601

(Pick Line 4) & OK (Click the NDIV box) 8 (Click the SPACE box) 0.3 & OK

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Nyquist/Haghighi

ABE 601

Click the Free button Click the Mesh button (Pick the rectangle) & OK

Click the Mapped button Click the Mesh button (Pick the rectangle) & OK & OK

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Nyquist/Haghighi

ABE 601

Click the Clear button (Click on Pick All) Click on Lines CLEAR button (Pick All)

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Nyquist/Haghighi

ABE 601

Area Sizing Command The area sizing command (AESIZE) controls the element size inside any area or on the face(s) of any volume. For any line on the area not having its own size assignment and not controlled by keypoint size assignments, the AESIZE command specifies the element size along the line as well, so long as no adjacent area has a smaller size, which would take precedence. Entering a smaller value will create smaller elements (a more dense mesh) while entering a larger value will create larger elements (a more coarse mesh).

Click on the Areas SET button (a picker will appear) (Pick area 1) & OK (the window shown above will appear) (Click the SIZE box) 3 & OK Click the Mesh button (Pick the rectangle) & OK

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Nyquist/Haghighi

ABE 601

Click the Clear button (Click on Pick All) Click on Areas CLEAR button (Pick All) Click on the Lines SET button (Pick All) & OK (Click the SIZE box) 3 & OK Click the Tri Shape button Click the Free button Click the Mesh button (Pick the rectangle) & OK

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Nyquist/Haghighi

ABE 601

Click on the Areas SET button (Pick area 1) & OK (Click the SIZE box) 1 & OK Click the Mesh button (Pick the rectangle) & OK & OK

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Nyquist/Haghighi

ABE 601

Click the Clear button (Click on Pick All)

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Nyquist/Haghighi

ABE 601

3. Modifying the Geometry and Re-meshing (Go To Main Menu) (Go To Preprocessor) Modeling Create Areas Circle Solid Circle (Click WP X box) 10 (Click WP Y box) 5 (Click Radius box) 4 OK Operate Booleans Subtract Areas (Pick base area from which to subtract) Click on the Rectangle (area 1) & OK (Pick area to be subracted) Click on the Circle (area 2) & OK

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