WS5-1 ADM704-705, Workshop 5, August 2005 Copyright 2005 MSC.Software Corporation WORKSHOP 5 PARAMETERIZING A NEW MODEL.

WS5-1ADM704-705, Workshop 5, August 2005Copyright 2005 MSC.Software Corporation

WORKSHOP 5

PARAMETERIZING A NEW MODEL



WORKSHOP 5 - PARAMETERIZING A NEW MODEL Problem statement

You are the designer of the hood mechanism for a storage compartment. The new design of the compartment has an air filter that needs to be changed frequently. You need to design the linkage so that the hood does not interfere with the filter when it is opened. By building parametric model, you can study different design configurations.


Getting startedTo import the model:

1. Start ADAMS/View from the mod_05_hood directory.2. Import the basic model in hood_start.cmd.

WORKSHOP 5 - PARAMETERIZING A NEW MODEL


Creating design points Now you’ll create four design points on ground. These points will be

the basis on which you build the rest of the model.

To create the design points:

1. On the Main Toolbox, double-click the Point tool . (Double-clicking the tool puts the tool in repeat mode and lets you to create multiple points without selecting the tool again.)

2. In the Main Toolbox container, ensure that the options are set to the defaults Add to Ground and Don’t Attach.



3. Click on the ADAMS/View window in four different places to create four different points in roughly the area shown above. Don’t worry about placing the points exactly because you will set their initial locations later.

4. Select the Select tool to turn off repeat mode.



To rename the points:1. Using the mouse, draw a box around the four points you've just

created to select them.2. From the Edit menu, select Appearance, set Visibility and Name

Visibility to On, and then select OK.Now you will see the points and their names.

3. Rename the points to POINT_1, POINT_2, POINT_3, and POINT_4. (To rename a point, right-click the point, point to the name of the point, and then select Rename.)



To set their initial locations: Using the Table Editor, set the point locations to the configuration

for the initial design.

1. From the Tools menu, select Table Editor.2. If necessary, at the bottom of the Table Editor, select Points.3. In the cells, change the location of the points as shown in the table

below.



4. Select OK.The points should appear as shown below:



Creating links Now you will create links between the points. All the links will be of

the same width and depth so you can quickly create the links by setting the desired options and then setting the Link tool to repeat mode.

To create links:

1. From the Main Toolbox, select the Link tool .2. In the container, set the options to:

New Part Width: 2.0 cm Depth: 2.0 cm

Tip: Be sure to select the check boxes for width and depth to ensure that ADAMS/View uses these values.



3. Double-click the Link tool to set repeat mode. 4. Create four links:

Link from PT_B to POINT_4 Link from PT_D to POINT_3 Link from PT_E to POINT_2 Link from PT_A to POINT_2

Note the following as you draw the links: As you select the points, ADAMS/View automatically parameterizes the

link to the design point locations. Therefore, when you select the locations, make sure you pick the actual

points, not other markers that might be located on top of the points. When prompted for a location, right-click the top of the point and choose

the desired point from the select list. This ensures that the point was selected.



5. Select the Select tool to turn off repeat mode. The links should appear as shown below:



Creating connections between the links Now you’ll connect the links using revolute joints, inline joint

primitives, and a spring-damper.

To create revolute joints:1. From the Main Toolbox, select the Revolute Joint tool .2. In the container, set the options to:

2 Bod -1 Loc Normal to Grid

3. Double-click the Revolute Joint tool to set repeat mode.



4. Create five revolute joints, taking care to select the correct design point:

Revolute joint at PT_A (between PART_5 and ground) Revolute joint at PT_B (between PART_2 and ground) Revolute joint at PT_D (between PART_3 and PART_1) Revolute joint at PT_E (between PART_4 and PART_1) Revolute joint at POINT_1 (between PART_3 and PART_5)

5. Select the Select tool to turn off repeat mode.



To create inline joint primitives: You will use the Joint Palette to create inline joint primitives.

1. From the Build menu, select Joints.2. Select the Inline Joint Primitive tool. 3. In the container, set the options to:

1 Location - Bodies Impl. Normal to Grid

4. Double-click the Inline Joint Primitive tool to set repeat mode. 5. Create two inline joint primitives, again taking care to pick the

correct design points: Inline joint primitive at POINT_2 (between PART_4 and PART_5) Inline joint primitive at POINT_3 (between PART_2 and PART_3)

6. Select the Select tool to turn off repeat mode. 7. Close the Joint Palette.



To create the spring-damper:1. From the Main Toolbox, select the Translational Spring-Damper

tool . 2. Create the spring-damper from PT_C to the marker on PART_2 at

POINT_4.Tip: Because both PT_C and POINT_4 are on ground, be sure to select the marker belonging to PART_2 at POINT_4 (for example, MARKER_126) not POINT_4.

3. Parameterize the spring marker (at POINT_4) with the expression:(LOC_RELATIVE_TO ({0,0,0}, POINT_4))



To modify the spring-damper parameters:1. Right-click the spring-damper, and then select Modify.2. Set Stiffness Coefficient to (90(newton/mm)).3. Set Damping Coefficient to (8(newton-sec/mm))4. In the Preload text box, enter 0.5. Change the Default Length option menu to Length at Preload,

and in the text box that appears, enter 250. 6. Select OK.



The connected hood should look like the following.



Testing the parameterization Now you’ll test the work that you’ve done so far. You’ll verify that

the model has only one degree of freedom (DOF), and then simulate and animate it to see how the hood opens.

To test the parameterization:

1. From the Information tool stack on the status bar, select the Model Verify tool , and then verify that the model has only one DOF. (If it doesn’t, go back through the steps and see if you can find your error.)

2. Simulate the model: End Time: 1.0 Steps: 50

3. As the model simulates, confirm that the hood opens.



4. Does the hood interfere with the filter? _______ Yes _______ No5. Animate as desired to observe the behavior of the hood

mechanism.6. Look at the strip chart of the measure FUNCTION_MEA_Y to see

the displacement of the hood marker relative to the marker representing the top surface of the hood. (If the strip chart is not visible, from the Build menu, point to Measure, select Display, and then double-click on this measure from the Database Navigator.)



Moving design points to see the effect on the design Because you have parameterized the model to be dependent on

the design point locations, you can move the design points to see their effect on the design.

To move the design points to a second configuration:

1. Using the Table Editor, change the location of the points as shown in the table below.




3. Does the hood interfere with the filter? _______ Yes _______ No



To move design points to a third design configuration:1. Again using the Table Editor, change the location of the points as

shown in the table below.




3. Does the hood interfere with the filter? _______ Yes _______ No



The following figure compares the fully opened hood for each design configuration:



Moving points using the move tools

Move the points using the move tools to identify shortcomings in the way the model was parameterized, such as a joint not at an intersection, or a joint not along line. Both x and y-values must be manipulated, as illustrated in the following figures:



In this section, you learned how to parameterize a model using design points. In the next module, you will learn how to create design variables, use them in your parametric model, and perform a design study to see the effect that these variables have on the hood motion.



WS5-1 ADM704-705, Workshop 5, August 2005 Copyright 2005 MSC.Software Corporation WORKSHOP 5 PARAMETERIZING A NEW MODEL.

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