Chapter 7 Parametric Modeling Parametric Modeling Contents Dimension

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Chapter 7 Parametric Modeling

Chapter 7 Parametric Modeling

Parametric Modeling Contents Dimension References • Promoting Parameters • Promoting Dimension References • Promoting

Parametric Modeling Contents Dimension References • Promoting Parameters • Promoting Dimension References • Promoting Feature Dimensions • Parameter Manager • Driven/Dependent Parameters • Auxiliary Variables • Parameter Functions • Workshop 7 -1, Pulley Model w/ Parameters ANSYS Workbench - Design. Modeler • Training Manual December 17, 2004 Inventory #002176 7 -2

Parametric Modeling Dimension References When sketches and features are created, their properties are controlled

Parametric Modeling Dimension References When sketches and features are created, their properties are controlled by what are called “dimension references”. Dimension references • Dimension references can be promoted to Design Parameters: – Allows parametric exchange of data. – Makes DM models more flexible to work with. – Is a key component in employing optimization (Sim) techniques. ANSYS Workbench - Design. Modeler • Training Manual December 17, 2004 Inventory #002176 7 -3

Parametric Modeling Promoting Parameters In the details box, click to promote a dimension reference

Parametric Modeling Promoting Parameters In the details box, click to promote a dimension reference to a design parameter “D”. – Use the default name or assign a more meaningful name (no spaces, underscore OK). – Notice, the value is no longer editable from the Details window. Note: you cannot undo promotion of attached CAD parameters. ANSYS Workbench - Design. Modeler • Training Manual December 17, 2004 Inventory #002176 7 -4

Parametric Modeling Promoting Dimension References Dimension parameters: – Default sketch dimension names indicate the

Parametric Modeling Promoting Dimension References Dimension parameters: – Default sketch dimension names indicate the associated plane as well as the specific dimension. – Syntax is “Plane_reference. Dimension_type_and_number”. – Example: • Using the example below, the default name for the parameter reads “XYPlane. D 4”. – XYPlane: indicates on which plane the dimension is located. – D 4: indicates the specific dimension is Diameter number 4. – It can be easily changed. ANSYS Workbench - Design. Modeler • Training Manual December 17, 2004 Inventory #002176 7 -5

Parametric Modeling Promoting Feature Dimensions Feature dimensions: – Default feature dimension names indicate the

Parametric Modeling Promoting Feature Dimensions Feature dimensions: – Default feature dimension names indicate the operation as well as the dimension reference number (“FD” indicates Feature Dimension). – Syntax is “Operation_type. Feature_Dimension_number”. – Using the example below the default name for the parameter reads “Extrude 1. FD 1”. – The name contains 2 pieces of information: • Extrude 1 indicates the parameter references the first extrusion created. ANSYS Workbench - Design. Modeler • Training Manual • FD 1 indicates it is parameter value 1 for the extrusion (see above; December 17, 2004 FD 0= rotation angle, FD 1= depth, FD 2 = Z axis rotation) Inventory #002176 7 -6

Parametric Modeling Parameter Manager After specifying parameters DM uses the Parameter manager to work

Parametric Modeling Parameter Manager After specifying parameters DM uses the Parameter manager to work with them. – Click the “Parameter” button on the GUI to expose parameter manager tools. ANSYS Workbench - Design. Modeler • Training Manual December 17, 2004 Inventory #002176 7 -7

Parametric Modeling Parameter Manager… The parameter manager window exposes 3 tabs allowing access to

Parametric Modeling Parameter Manager… The parameter manager window exposes 3 tabs allowing access to specific parametric tools: • Design Parameters tab: – Each design parameter is listed here. – Parameter values are reviewed and changed here. – Use the ‘#’ to add comments to parameter definitions. ANSYS Workbench - Design. Modeler • Training Manual December 17, 2004 Inventory #002176 7 -8

Parametric Modeling Parameter Manager… Parameter/Dimension Assignment tab: ANSYS Workbench - Design. Modeler • Training

Parametric Modeling Parameter Manager… Parameter/Dimension Assignment tab: ANSYS Workbench - Design. Modeler • Training Manual – Lists a sequence of “left-hand-side = right-hand-side” assignments (equations) which are used to drive the model dimensions by the given Design Parameters. – The left-hand side is a reference to one of the plane/sketch or feature dimensions or a reference to an auxiliary “variable”. – The right-hand side is an arbitrary expression in +, -, *, and /, including parentheses, referencing Design Parameters (here, the syntax uses the '@' prefix) and feature dimensions, but also numeric constants or references to auxiliary variables. – Can also use ^ for exponential, and % for modulus (remainder of x/y) – Functions (discussed later) can also be used. December 17, 2004 Inventory #002176 7 -9

Parametric Modeling Parameter Manager… Training Manual • XYPlane. R 3 = @Hole_Size • Indicates

Parametric Modeling Parameter Manager… Training Manual • XYPlane. R 3 = @Hole_Size • Indicates that a design parameter named “Hole_Size” has been defined for a radial dimension reference lying on the XY plane. • A sample comment has been added to the parameter assignment. ANSYS Workbench - Design. Modeler – Design. Modeler will evaluate the right-hand side of each expression, and use the resulting value to drive the dimension referenced in the left-hand side. – Design parameter names are preceded by @. – Comments can be added preceded by the #. – Example (from previous page): December 17, 2004 Inventory #002176 7 -10

Parametric Modeling Driven/Dependent Parameters Driven parameters are parameters which take on values based on

Parametric Modeling Driven/Dependent Parameters Driven parameters are parameters which take on values based on the value of a “driving” design parameter. – Goal: given the rectangular section shown here, with dimensions S 1 for height and S 2 for width, drive the value of the width according to the formula, S 2 = 2*S 1. S 2 S 1 • In Design. Modeler we would proceed as follows: – – Dimension the sketch height and width. Create a design parameter called S 1 will be our “driving” parameter. Continued. . . ANSYS Workbench - Design. Modeler • Training Manual December 17, 2004 Inventory #002176 7 -11

Parametric Modeling Driven/Dependent Parameters… Training Manual • Remember!: The “H” in H 1 indicates

Parametric Modeling Driven/Dependent Parameters… Training Manual • Remember!: The “H” in H 1 indicates a horizontal dimension while the “V” in V 2 indicates a vertical dimension. – From the Parameter/Dimension Assignments notice the dimension assignment for S 1 is: – Knowing the “internal” parameter name for our driven parameter will be “XYPlane. H 1” we can type the following formula in the Parameter/Dimension Assignment tab: ANSYS Workbench - Design. Modeler – By inspecting the details for our sketch (previous page) we can see the width dimension assignment is called H 1. December 17, 2004 Inventory #002176 7 -12

Parametric Modeling Driven/Dependent Parameters… Training Manual • WAIT! If the regeneration of the model

Parametric Modeling Driven/Dependent Parameters… Training Manual • WAIT! If the regeneration of the model fails due to a mistake in our formula, we could encounter problems trying to undo the operation. – Fortunately Design. Modeler contains a more elegant solution to validating parametric formulae: • By moving to the “Check” tab, parametric assignments are evaluated and the result displayed. • Let’s take a closer look at the Check feature. . . ANSYS Workbench - Design. Modeler – At this point we could verify our formula by simply changing values for S 1, re-generating the model, and checking to make sure the width is always equal to 2*S 1. December 17, 2004 Inventory #002176 7 -13

Parametric Modeling Driven/Dependent Parameters… The check window is split into two output sections: Parameter/Dimension

Parametric Modeling Driven/Dependent Parameters… The check window is split into two output sections: Parameter/Dimension Assignments Design Parameter Assignments – The sections are listed as “output” since each definition is displayed according to its definition as well as its output value. – In the above case, it can be seen that our parameter “S 1” is assigned a value of 35. 000 (design parameter section). – Similarly, our driven parameter “XYPlane. H 1” evaluates to 70. 000. – Since we wish to drive XYPlane. H 1 to the value 2*S 1 we verify the value of 70. 000 makes sense. ANSYS Workbench - Design. Modeler • Training Manual December 17, 2004 Inventory #002176 7 -14

Parametric Modeling Auxiliary Variables Training Manual Auxiliary variables are parameters that do not directly

Parametric Modeling Auxiliary Variables Training Manual Auxiliary variables are parameters that do not directly define a sketch or feature dimension. • Typically used as a constant value or factor. • Example: – – ANSYS Workbench - Design. Modeler • Here we have defined 2 design parameters (@Height and @Length). We now create a variable named “factor” using the formula shown. Finally, we set the radius dimension “R 5” equal to our variable. Note, this example is for demonstration only. We could have simply directly defined R 5 with the formula used to define the variable. December 17, 2004 Inventory #002176 7 -15

Parametric Modeling Parameter Functions can be utilized to capture Design Intent and other relationships

Parametric Modeling Parameter Functions can be utilized to capture Design Intent and other relationships among parameters. – Functions are operations that return a single value • ABS(X) • EXP(X) • LN(X) • SQRT(X) • SIN(X) (in degrees) • COS(X) • TAN(X) • For X between – 1 and +1. • – ASIN(X) & ATAN(X) (return value between -90 & 90 degrees) – ACOS(X) (returns value between zero & 180 degrees) Examples… – A=acos(-1) – B=abs(X) # # evaluates to – 90 evaluates to |X| ANSYS Workbench - Design. Modeler • Training Manual December 17, 2004 Inventory #002176 7 -16

Workshop 7 -1, Pulley Model w/ Parameters Goals: – Create a 3 D model

Workshop 7 -1, Pulley Model w/ Parameters Goals: – Create a 3 D model through sketching and extruding. – Add a revolved feature to represent the pulley’s groove. – Add a bolt hole pattern with one sketch that is based on a construction sketch. – Parameterize the model so the pulley size automatically updates the bolt hole pattern. A whole range of pulley sizes could now be simulated! • Start Page setup: – Choose to create new geometry, or >File>New – At the prompt, set the length unit to millimeter ANSYS Workbench - Design. Modeler • Training Manual December 17, 2004 Inventory #002176 7 -17

Workshop 7 -1, Pulley Model w/ Parameters In Tree, click on >XYPlane to activate

Workshop 7 -1, Pulley Model w/ Parameters In Tree, click on >XYPlane to activate it Toolbar: “Look At” 1. [Sketching] > Draw > Circle 1 Note: selecting the Sketching tab after selecting a plane changes to Sketching mode and automatically creates a new sketch if one does not exist ANSYS Workbench - Design. Modeler Create a sketch on the XYPlane: Training Manual December 17, 2004 Inventory #002176 7 -18

Workshop 7 -1, Pulley Model w/ Parameters Training Manual • Select origin for center

Workshop 7 -1, Pulley Model w/ Parameters Training Manual • Select origin for center of circle 2. Put the cursor near the global origin. You should see a “P” appear near your cursor, indicating an auto-constraint will be applied. Click once with the left mouse button. • Select an arbitrary point for diameter of circle 3. Click on the screen to define the radius of the circle. The actual value does not matter, as we will dimension this next. • [Sketching] > Dimensions > General 4. RMB and choose Diameter dimensioning, then click on the circle. Click again on the screen to place the dimension. • Details View: Dimensions > D 1 5. Click on the text box value next to “D 1”. This will highlight the text entry field. Enter “ 60” for the value of D 1. This redefines the diameter as 60 millimeters. 4 3 2 5 ANSYS Workbench - Design. Modeler Create a sketch on the XYPlane (cont’d): December 17, 2004 Inventory #002176 7 -19

Workshop 7 -1, Pulley Model w/ Parameters Training Manual ANSYS Workbench - Design. Modeler

Workshop 7 -1, Pulley Model w/ Parameters Training Manual ANSYS Workbench - Design. Modeler Extrude the circle to create a cylinder • Graphics View: Select Iso View ball 6. Select the light-blue iso-ball on the triad to change to isometric view. • Toolbar: Extrude 7. Select the Extrude icon on the 3 D Features Toolbar. 7 9 • Details View: FD 1, Depth (>0) 8. Select the text entry box next to “FD 1, Depth (>0)” in the Details View. Enter a value of “ 10” to extrude the sketch 10 millimeters in the positive z-direction. • Toolbar: Generate 9. Select the Generate icon on the Toolbar to generate the cylinder. 8 6 December 17, 2004 Inventory #002176 7 -20

Workshop 7 -1, Pulley Model w/ Parameters Training Manual Toolbar: “New Sketch” (creates Sketch

Workshop 7 -1, Pulley Model w/ Parameters Training Manual Toolbar: “New Sketch” (creates Sketch 2 on XY plane) [Sketching] > Draw > Polygon n=5 10. Put the cursor near the global origin. You should see a “P” appear near your cursor, indicating an auto-constraint of “Coincident Point” will be applied. Click once with the left mouse button to define the center of the polygon. 11. Put the cursor near the positive Y axis. You should see a “C” appear near the cursor indicating the point is coincident to the Y axis. Click once with the left mouse button to define the top vertex location. 11 10 ANSYS Workbench - Design. Modeler Toolbar: “Look At” icon (XYPlane is already active) December 17, 2004 Inventory #002176 7 -21

Workshop 7 -1, Pulley Model w/ Parameters Training Manual [Sketching] > Dimensions > Vertical

Workshop 7 -1, Pulley Model w/ Parameters Training Manual [Sketching] > Dimensions > Vertical 12. Dimensions the polygon as shown at right. 13. Select the text entry box next to “V 2” and enter a value of 20 mm. 12 13 ANSYS Workbench - Design. Modeler Dimension the 5 sided polygon December 17, 2004 Inventory #002176 7 -22

Workshop 7 -1, Pulley Model w/ Parameters Training Manual Note: XYPlane is still active

Workshop 7 -1, Pulley Model w/ Parameters Training Manual Note: XYPlane is still active Toolbar: “New Sketch” icon (creates Sketch 3 on XY plane) 14 Toolbar: “Look At” icon [Sketching] > Draw > Circle 14. Put the cursor near the top vertex until a “P” appears near your cursor, indicating an auto-constraint will be applied. Click to define the center of the circle then drag the cursor to define the circle radius. 15 15. Repeat the above step at each of the (5) vertices of the polygon. ! IMPORTANT: watch for the “R” to appear next to the cursor before clicking to define each radius. This indicates the new circle is radially constrained to the previous circle. ! Note: if you inadvertently fail to apply auto constraints, you can undo the selection and try again, or use >Constraints tab and apply them manually. ANSYS Workbench - Design. Modeler Create the holes for the bolt pattern: December 17, 2004 Inventory #002176 7 -23

Workshop 7 -1, Pulley Model w/ Parameters [Sketching] > Dimensions > Diameter 16. Click

Workshop 7 -1, Pulley Model w/ Parameters [Sketching] > Dimensions > Diameter 16. Click on the top circle created in step 14. 17. Specify 5 mm diameter in the dimension Detail. • Note: vary the dimension several times to see if all circles update to the new value. Can use >Dimensions>Animate too! Remember to make final dimension 5 mm before moving on to the next step. 16 17 ANSYS Workbench - Design. Modeler Dimension the top circle: Training Manual 8 mm December 17, 2004 Inventory #002176 7 -24

Workshop 7 -1, Pulley Model w/ Parameters Toolbar: Extrude • Details: 18. Operation: “Cut

Workshop 7 -1, Pulley Model w/ Parameters Toolbar: Extrude • Details: 18. Operation: “Cut Material” 19. Type: “Through All” 20 20. “Generate” 18 19 ANSYS Workbench - Design. Modeler Extrude Sketch 3 to create the bolt holes Training Manual December 17, 2004 Inventory #002176 7 -25

Workshop 7 -1, Pulley Model w/ Parameters Training Manual 21. Click on >ZXPlane in

Workshop 7 -1, Pulley Model w/ Parameters Training Manual 21. Click on >ZXPlane in Tree to make it active 22 22. Toolbar: “New Sketch” • Toolbar: “Look At” icon • Sketching: Draw > Rectangle – Draw a rectangle in the approximate location shown at right 21 ANSYS Workbench - Design. Modeler Create a sketch to revolve around the pulley in order to define the pulley groove December 17, 2004 Inventory #002176 7 -26

Workshop 7 -1, Pulley Model w/ Parameters 23. [Sketching] > Dimensions Using the dimension

Workshop 7 -1, Pulley Model w/ Parameters 23. [Sketching] > Dimensions Using the dimension toolbox add dimensions as shown here ANSYS Workbench - Design. Modeler Dimension the sketch Training Manual December 17, 2004 Inventory #002176 7 -27

Workshop 7 -1, Pulley Model w/ Parameters Training Manual > Modeling>ZXPlane > Sketch 4

Workshop 7 -1, Pulley Model w/ Parameters Training Manual > Modeling>ZXPlane > Sketch 4 29 24 24. Toolbar: Revolve 25. Click on the Z axis in the graphics window 26. Click >Apply 25 27. Change the Operation to “Cut Material” 28. Change “FD 1, Angle” to 360 29. Generate the feature 26 30. Click on the Blue Triad ISO Ball as desired. 27 ANSYS Workbench - Design. Modeler Create the pulley groove by revolving the sketch 28 December 17, 2004 Inventory #002176 7 -28

Workshop 7 -1, Pulley Model w/ Parameters Training Manual ANSYS Workbench - Design. Modeler

Workshop 7 -1, Pulley Model w/ Parameters Training Manual ANSYS Workbench - Design. Modeler With the pulley model completed as shown here we will now create a parameter for the pulley’s diameter and define several expressions to control the pulley’s features. December 17, 2004 Inventory #002176 7 -29

Workshop 7 -1, Pulley Model w/ Parameters Training Manual ANSYS Workbench - Design. Modeler

Workshop 7 -1, Pulley Model w/ Parameters Training Manual ANSYS Workbench - Design. Modeler [Modeling Tree] >XYPlane > Sketch 1 30. In the Sketch 1 Detail check the box next to D 1 This action will immediately cause a dialog box to be displayed containing the default dimension name. 31. Enter “Pulley_Dia” in the dialog box to name the parameter then OK. 31 30 December 17, 2004 Inventory #002176 7 -30

Workshop 7 -1, Pulley Model w/ Parameters Training Manual Recall the original dimensions were:

Workshop 7 -1, Pulley Model w/ Parameters Training Manual Recall the original dimensions were: Pulley_Dia = 60 Hole pattern = 20 Groove radius = 28 The desired formulae are: a) Hole pattern placement • Dimension = (Pulley_Dia) / 3 b) Pulley groove diameter. – Dimension = (Pulley_Dia)/2 - 2 ANSYS Workbench - Design. Modeler Note: we have now made the pulley diameter a parametric value. Since our goal is to “drive” the other dimensions to automatically reflect any diameter change, we’ll now create several expressions for that purpose. In particular, there are 2 dimensions we need to control, the hole pattern dimension and the pulley’s groove radius (see below). December 17, 2004 Inventory #002176 7 -31

Workshop 7 -1, Pulley Model w/ Parameters Training Manual Toolbar: Parameters 32. Click on

Workshop 7 -1, Pulley Model w/ Parameters Training Manual Toolbar: Parameters 32. Click on the “Parameter/Dimension Assignments” tab to enter equations. • NOTE: Your default parameter names may be different depending on the order and type of >Dimensions placed. • Click on your various sketches in the Tree to display your default names in the Detail Window • This equation is for the overall size of the bolt pattern that lies on the XY plane. • This equation is for the groove sketch radial dimension line. This sketch lies on the ZX plane. Hole Pattern Size is Dia/3 32 ANSYS Workbench - Design. Modeler Activate the parameter manager via the toolbar icon The Groove is placed at “Dia/2 minus 2 mm”. The “minus 2” insures it always December 17, 2004 Note: Your default parameter names may be different Inventory #002176 cuts a 2 mm deep groove. 7 -32

Workshop 7 -1, Pulley Model w/ Parameters Experiment with new values for “Pulley_Dia” and

Workshop 7 -1, Pulley Model w/ Parameters Experiment with new values for “Pulley_Dia” and click “>Check” tab after each change. Notice the “driven” dimensions can be viewed and evaluated with their updated values. Pulley_Dia = 40 mm Pulley_Dia = 150 mm Note: Your default parameter names may be different ANSYS Workbench - Design. Modeler Return to the “Design Parameter” tab Training Manual December 17, 2004 Inventory #002176 7 -33

Workshop 7 -1, Pulley Model w/ Parameters Note how all model dimensions update simultaneously.

Workshop 7 -1, Pulley Model w/ Parameters Note how all model dimensions update simultaneously. This could represent an entire range of pulley sizes (part family) or a series of design variations to used in optimization. ANSYS Workbench - Design. Modeler Once again, experiment with new values for “Pulley_Dia”, this time “generating” the model after each change. Training Manual December 17, 2004 Inventory #002176 7 -34