Workshop 1 preparing a can-crusher presentation

Workshop 1 – Preparing a Can-Crusher Presentation Problem statement You have just been promoted to a high-profile project. Your supervisor is responsible for the dynamic analysis of a can-crushing mechanism. He wants you to prepare a presentation that includes: Table of eigenvalues from Adams/Linear Screen snapshot (.jpg) of system mode 8 A plot of the y-component of the torque in a revolute joint versus the distance the can has been compressed Animation movie files (.avi) of the flexible body model alongside the rigid body model A Web page with the presentation. For example:

Workshop 1 – Can-Crusher Presentation (Cont.) Point out the general subdirectory structure used throughout the course. Ask how many students present their Adams results through movies or Web presentations. Cover plotting with an independent axis that isn’t time. This will be needed for the plotting section of this workshop. Demonstrate the use of overlay in PPT with a simple model such as a swinging cylinder.

Workshop 1 – Can-Crusher Presentation (Cont.) Mechanism information This model represents a can-crushing mechanism, as shown in Figure 1: Can Plunger Node 2505 Base Node 2502 flx_lever Coupler Node 2498

Workshop 1 – Can-Crusher Presentation (Cont.) The mechanism includes the following parts:

Workshop 1 – Can-Crusher Presentation (Cont.) An input force is applied to the end of FLX_LEVER with a STEP function and turns off after 0.55 seconds. Force

Workshop 1 – Can-Crusher Presentation (Cont.) Setting up the model To set up the model: Start Adams/View from the directory exercise_dir/mod_01_cancrusher. Where exercise_dir is the directory where the workshop subdirectories reside. From the same directory, import the model command file cancrusher_start.cmd. ADAMS/View displays the model named cancrusher. Inspecting the flexible lever You can quickly inspect the flexible lever to see how each mode would contribute to its deformation.

Workshop 1 – Can-Crusher Presentation (Cont.) To inspect the flexible lever: From the Main Menu, select the Isometric tool then press the Wireframe/Shaded button in the Status Toolbar. Turn off icon (v) and grid visibility (g). You can turn on and off the icon and grid visibility as needed throughout the course. If the strip chart is blocking the view, you can move it aside. Right-click FLX_LEVER, point to Flexible_Body: FLX_LEVER, and then select Modify. In the Mode Number text box, enter 10, and then press Enter. ADAMS/View displays mode 10 superimposed on the undeformed body: After importing the model, many students will instinctively try to run the model from the Main Toolbox. Advise the students not to do this because this model requires FLEX_SCRIPT. Mode 10

Workshop 1 – Can-Crusher Presentation (Cont.) In the Flexible Body Modify dialog box, select the Animate tool . Adams/View animates mode 10 for three cycles. To see how Adams/View displays the deformation mode and the undeformed body, toggle the Superimpose option a few times. Set Plot Type to Contour. The resulting contours show deformation, not stress. To exaggerate the results, set Deformation Scale Factor to 2.0, and then press Enter.

Workshop 1 – Can-Crusher Presentation (Cont.) Animate mode 10 once again and note the difference caused by the increased deformation scale factor. Review modes 7 - 28. The first six modes are rigid body modes and are automatically disabled because Adams/Flex already handles the dynamics for those modal degrees of freedom. Set Deformation Scale Factor back to 1.0.

Workshop 1 – Can-Crusher Presentation (Cont.) Simulating the rigid lever Make the lever temporarily rigid, and then simulate it to observe the can-crushing operation. To simulate the rigid lever: Set Inertia modeling to Rigid body. Select OK. Confirm that the flexible body is not selected. From the Main Menu press Clear the Select List . You should do this whenever you want to stop seeing the model in a dimmed appearance. Under the Simulation tab, click Run a Scripted Simulation in the Simulate group.

Workshop 1 – Can-Crusher Presentation (Cont.) Run scripted simulation using the script .cancrusher.RIGID_SCRIPT. The script uses the following Adams/Solver commands: SIM/STATICS INTEGRATOR/GSTIFF, HMAX=.01 SIM/TRANSIENT, END=0.75, STEPS=50 The strip chart CAN_COMPRESSION_MEA displays the deformation of the can versus time.

Workshop 1 – Can-Crusher Presentation (Cont.) From the Simulation Control dialog box, select the Save Simulation Results tool . Save the results with the name rigid. You will use these results later in your presentation material. Animate the results of the simulation (Results tab, Animation icon). The lever arm stays blue because it’s not deforming. It is not deforming because you set Inertia Modeling to Rigid Body. Close the Animation Controls dialog box or reset the model to the modeling view by other means. Make sure students save the rigid results since they’ll use them later.

Workshop 1 – Can-Crusher Presentation (Cont.) Simulating the flexible lever Make the lever flexible again, and then simulate it to observe its motion. To simulate the flexible lever: Right-click FLX_LEVER, point to Flexible_Body: FLX_LEVER, and then select Modify. In the Flexible Body Modify dialog box, set Damping Ratio to default. Deformations of the flexible body are displayed relative to the datum node. You'll choose node 2505 because it is at the opposite end of the applied load, as shown in Figure 1. The colors indicate the magnitude of the deformation: red indicates the most deformation, blue the least. Clear the selection of LBRF. In the Datum Node text box, enter 2505. Set Inertia modeling to Partial coupling. Partial coupling is the default flexible body representation of the inertia invariants. Select OK. Clear the selection of the lever.

Workshop 1 – Can-Crusher Presentation (Cont.) Perform another scripted simulation using .cancrusher.FLEX_SCRIPT. The script uses the following Adams/Solver commands: SIM/STATICS LINEAR/EIGENSOL INTEGRATOR/GSTIFF, SI2, HMAX=0.01 SIM/TRANSIENT, END=0.75, STEPS=50 Save the simulation results as flexible. Animate the results of the simulation. By animating the results you've seen how the flexible lever deforms as the load is applied. You may have noticed in the script that an Adams/Linear eigenvalue solution was performed at the static position. In the next section you will learn how to export a table of eigenvalues and create an image of one of the eigenmodes which will be used in your presentation.

Workshop 1 – Can-Crusher Presentation (Cont.) Preparing the eigenvalue data table For your presentation, generate a table of system eigenvalues from Adams/Linear and export it to a text file. To prepare the data table: Under the Results tab, click Postprocessor or press F8. Right-click the viewport, and then select Load Mode Shape Animation. From the Database Navigator, under flexible, double-click the Eigen results (for example, EIG_1). Adams/PostProcessor displays the model and updates the dashboard with mode shape animation controls. From the dashboard, select Table of Eigenvalues. The Information window displays the table. Select Save to File, and save the file as system_modes.txt (in the Completed folder). Close the Information window. If students can't create the table of Adams/Linear eigenmodes, they probably didn't use FLEX_SCRIPT. To save time, have them use misc/system_modes.txt. If the table of system modes differs, it’s possible students forgot to choose default damping for the flexible body.

Workshop 1 – Can-Crusher Presentation (Cont.) Creating an image of the lever For your presentation, create a color image of system mode 8 and name it mode_8.jpg. Figure 2. System Mode 8

Workshop 1 – Can-Crusher Presentation (Cont.) To create the image: To display the triad, from the dashboard, select the View tab, and then select Display Triad. For optimal viewing, fit the model in the viewport by using the view control keyboard shortcuts, rotate, zoom, and translate so that you have a view of the model similar to the view in Figure 2. From the dashboard, select the Mode Shape Animation tab. Set Mode Number to 8, to display mode 8 and its frequency. Note its frequency: _____(hz). Change the Scale Factor to 0.1. To animate mode 8, select the Play tool . If mode 8 looks like a king cobra snake, then the deformation scale is too large (probably 15.0). Make sure the students use a deformation scale of 1.0 or 2.0.

Workshop 1 – Can-Crusher Presentation (Cont.) Observe the mode shape animation, and when you’ve finished animating, press the Pause tool . Why do you think that mode 8 is important? ________________________________________________________________________________________________________________________________________________________________________ Select the Reset tool . Pull down File > Print. Set Print to File. In the File Name text box, enter mode_8.jpg. Set the pull-down menu, directly under File Name, to JPG. Select OK. Adams/PostProcessor creates the image file.

Workshop 1 – Can-Crusher Presentation (Cont.) Comparing animations You use Adams/PostProcessor to compare the animations of the rigid and the flexible levers. You compare animations using the overlay feature. Figure 3 shows how your window looks after you’ve completed the steps in this section.

Workshop 1 – Can-Crusher Presentation (Cont.) Figure 3. Overlaying Animation Results

Workshop 1 – Can-Crusher Presentation (Cont.) To compare animations: Delete the current page to remove the mode shape animation. From Adams/PostProcessor’s Main toolbar, from the Page layout tool stack, select the 2 Views, side by side tool . Right-click the viewport on the right, and then select Load Animation. Double-click rigid. For optimal viewing, fit the model in the viewport. As shown in Figure 3, overlay the simulation named flexible: From the dashboard, select the Overlay tab. In the Offset text box, enter -10, 0, 0. In the Colors text box, enter blue. Hold down the Control key and multiple-select .cancrusher.rigid and .cancrusher.flexible. Move the pointer out of the dashboard area, to execute the command (which can take a while). Fit the models in the viewport and then animate by selecting the Play tool. After you finish viewing the animation, pause it. When overlaying, the Analysis text box must contain .cancrusher.rigid. If students are having trouble, recap the demonstration you gave on page  and point them to Figure 3.

Workshop 1 – Can-Crusher Presentation (Cont.) Observing deformations Deformations of the flexible body are displayed relative to the datum node you assigned earlier, in Simulating the flexible lever. Increase the deformation scale so that you can better visualize the deformation in the movie file you will be creating soon. To exaggerate deformations: Right-click the flexible body, point to Flexible_Body: FLX_LEVER, and then select Select. In the Flex Props tab, set Scale to 20, and then press Enter. To clear the selection of the flexible body, select the Select tool . Animate again. Notice how increasing the scale factor has exaggerated the flexible lever deformations.

Workshop 1 – Can-Crusher Presentation (Cont.)

Workshop 1 – Can-Crusher Presentation (Cont.) Comparing joint torque plots As the lever crushes the can, you can see the combined twisting and bending of the lever. The twisting and bending produces force components that act as a torsional load on the revolute joint (at the coupler). The torque climbs until the can finally collapses from the crushing operation. At the end of the duty cycle, the load in the lever is relieved and the joint torque drops back to zero. The measure for the joint torque is named LVR_CPLR_REV_MEA_TY and you will plot it versus the deformation of the can, CAN_COMPRESSION_MEA.

Workshop 1 – Can-Crusher Presentation (Cont.) To compare plots: Right-click the viewport on the left and select Load Plot. If an alert box appears, select OK to dismiss it. In the dashboard, set Source to Measures. Set Independent Axis to Data, and then select CAN_COMPRESSION_MEA as the independent data measure. Select Surf. The Surf feature lets you quickly browse or surf through multiple results. Using it can eliminate mouse clicks and other operations, such as delete, undo, and so on. Select both the rigid and the flexible analyses, and plot LVR_CPLR_REV_MEA_TY. If the legend obscures the plot, select it and move it up slightly. Clear the selection of the legend. Select the viewport on the right, and then animate.

Workshop 1 – Can-Crusher Presentation (Cont.) Preparing the movie file To prepare the movie file: Click on the viewport on the right. From the dashboard, select the Animation tab. Choose a frame range of 1 to 50, and then press Enter. Reset the animation so it displays the first frame. For optimal viewing, fit the models in the viewport. To prepare for recording the .avi file, select the Record tab. Clear the File Name text box. In the File Name text box, enter the name movie. Verify that Format is set to AVI. Select the Record tool. Select Play. Note: Do not change windows during the record phase. After the animation goes through one pass, or 50 frames, select Pause. Note: Do not return to Adams/View because you will complete the next steps in Adams/PostProcessor.

Workshop 1 – Can-Crusher Presentation (Cont.) Publishing to the Web For publishing to the Web, you export data in the current session of Adams/PostProcessor as HTML pages for viewing by others in your organization. Adams/PostProcessor also creates: Plots and animations as .png, .jpg, .bmp, .xpm, or .tiff images. Movies of animations as .avi or .mpg. Information about the parts, constraints, forces, and more in the selected models. This is the same information that appears when you select Info.

Workshop 1 – Can-Crusher Presentation (Cont.) To publish to the Web: From the treeview in Adams/PostProcessor, select page_1. Pull down Edit > Rename and then rename the page to movie. From the main toolbar, select the Create a new page tool . Rename this page to system_modes. From the Page Layout tool stack , select the 1 View tool . Right-click the viewport, and then select Load Report. Double-click system_modes.txt. From the main toolbar, select the Create a new page tool. Rename this page to can_compression. Right-click the viewport, and then select Load Plot. Set Source to Measures. Plot the CAN_COMPRESSION_MEA for both the rigid and flexible bodies. During recording phase, Adams/View essentially performs a screencapture. Advise students to be sure not to change windows during this phase.

Workshop 1 – Can-Crusher Presentation (Cont.) Pull down File > Export > HTML Report. Select OK. Note: Do not change windows because the movie will be re-recorded. Adams/PostProcessor creates a folder, named html_export, in your working directory. From the Adams/PostProcessor Main toolbar, select to return to the modeling environment. Save the database using the default name. Exit Adams/View. Open the html_export folder. In a browser, open index.html. To view the results, expand the pages folder. Expand the cancrusher folder to browse information on the parts, constraints, and forces in the selected model.

Workshop 1 – Can-Crusher Presentation (Cont.) Module review How does the system mode 8 compare with the flexible body mode that is near the same frequency? ________________________________________________ Can you suggest a better reference frame in which to express the measure LVR_CPLR_REV_MEA_TY? To display aspect ratio (width and height):     In MS Photo Editor, it is displayed in the status bar at the bottom of the interface     On SGI, the imgworks program displays it in the upper border of the Motif window (details in README) in completed directory.