Workshop 4 Chain System Workshop

Model Description Wood Pusher System Files required: or only wood_pusher_start_xx.cmd or only wood_pusher_start_xx.bin where xx = latest version number Adams version required: 2012 or later

Launch Adams/View and Open the Model RMB on the Adams/View shortcut icon on the desktop and select Properties. Change the Start In box value to %1. Now create a copy of this icon in your working directory. The “%1” tells the shortcut to set the working directory of Adams to whatever folder the icon is located in. Now double click the shortcut in the working directory. When Adams/View starts up, select Existing Model. In the File Name, box, browse for the file wood_pusher_start_1.cmd and hit OK.

Viewing Options Practice the following: To toggle between solid and wireframe view, hit this icon on the bottom ribbon. To toggle icons on or off, use this icon icon on the bottom ribbon To select something, click on it. To unselect, click in the background or use the unselect icon. To rotate, hit r once and release, then hold the LMB down and move the mouse. You can change the rotation center with this icon on the top tool bar To zoom, hit z once and release, then hold the LMB down and move the mouse Other view options are provided on this tool bar: To translate, hit t once and release, then hold the LMB down and move the mouse. To fit the full model in the graphics window, hit f. To get back to the front view, hit <shift> f.

Set Working Units, Solver, and Grid Settings > Working Grid > check Show Working Grid Settings > Units… Settings > Solver > Executable… Pick C++

Run the Model Run a 5 second, 200 step simulation After the simulation completes, hit the rewind button. You can also hit the animation button to see the simulation again Currently there is a motion between the tool piece and the board. We will eventually replace this motion with a chain system.

Build the Sprocket Set From the Machinery tab, click on the sprocket icon Adams/Machinery supports two types of chain systems: Roller sprocket and Silent Sprocket. Roller sprockets are for use with traditional chains that use cylindrical pins for contact with the sprocket. Silent chains use an involute tooth for contact with the sprocket to reduce noise. Hit Next when the following form appears.

Build the Sprocket Set Change the method to 2D Links and then click Next. Note: This will actually create a 3D chain, but you are restricted to choose an axis of rotation that is parallel to one of the three global axes. If some other axis is required, you would choose 3D Links. Note that there is also an option called Constraint. This simply transmits motion through a velocity ratio.

Build the Sprocket Set The figure below shows how the geometric parameters for the sprocket are defined, which we will specify next.

Build the Sprocket Set On the Gear 1 tab of the Geometry-Sprocket form, fill in the fields circled in red as shown. Once this is done, the other fields will fill in automatically with defaults. Don’t hit Next yet!

Build the Sprocket Set Now complete the top portion of the Sprocket 2 tab as shown and hit Next.

Build the Sprocket Set Note: You can modify the default contact parameters for the sprocket set here, but we will go with the defaults. Accept the material properties defaults and hit Next.

Build the Sprocket Set Complete form as shown for Sprocket 1. Use the right mouse button to pick the body. Don’t hit Next yet.

Build the Sprocket Set Similar to how you picked the body for Sprocket 1, pick part fake as the body for Sprocket 2. Note: Fake is a dummy part (cylinder concentric with sprocket) necessary to later tie motion of the sprocket to a gear constraint. Hit Next.

Build the Sprocket Set Accept the output defaults by hitting Next.

Build the Sprocket Set Hit Next for this form

6/5/2018 Build the Sprocket Set The figure below defines the guide parameters, which we will specify next. MSC Software Confidential

Build the Sprocket Set Enter 1 for the number of guides. This will cause most of the form to auto-populate. Modify the form as shown. Make sure that Out is selected Click Next.

Build the Sprocket Set Right click in Material Type, select Material > Guesses > Steel. Click Next.

Build the Sprocket Set Click Finish on the Completion form.

Build the Sprocket Set After a minute or so, you should see the newly-created sprocket set.

Creating the Chain From the Machinery tab, click on the chain icon Right-click in the Sprocket Set Name field and select sprocketset_1 as shown (the sprocket set that you just created). After you see the Chain System Name field auto-populate with a default name (chainsys_1), click Next.

Creating the Chain When the Method form appears, accept the default of 2D Links and click Next.

Creating the Chain On the Compliance form, you can select different methods of specifying the compliance between the chain links and rollers (Linear, Non-linear, and Advanced). Note that there are no revolute joints between these chain components, just force elements like bushings or fields. Accept the default Linear and hit Next.

Creating the Chain Complete the Geometry form as shown below. Reference location is used internally for building the chain, but is generally not important for the user. By changing from uniform to multi, you can have different size links that alternate in position along the chain. Rotational (Z) Damping is intended to represent friction as the links rotate about the pins. Note that there are some visualization options under Geometry Settings. Click Next.

Creating the Chain The next form allows you to specify mass properties for the links. Accept the defaults and click Next.

Creating the Chain You now need to specify the wrapping order of the chain. Right-click in the Wrapping Order field and select sprocketset_1_driver Right-click in the Wrapping Order field and select sprocketset_1_driven Right-click in the Wrapping Order field and select sprocketset_1guide_guide After verifying the order shown, hit Next. Click Yes to the message below: Completed form

Creating the Chain After seeing a warning that the model is no longer compatible with the Fortran solver, close the message and check both boxes as shown below on the Output Request form. A span request looks at one fixed location in the model as chain links pass through it. By picking one link, Adams will look at various outputs at the design location of that chain part, including the region of one link on either side of it. By checking Motion average and Force average, you are instructing Adams to average outputs over that span region. Reference part is typically ground unless the sprockets are on moving parts.

Creating the Chain On the Chain Span tab, right click and pick one of the links in the Chain Part(s) field. Set Reference Part to Ground. If this field is not shown, click on the Chain Link tab, and then back to the Chain Span tab. Check Motion average and Force average.

Creating the Chain On the Chain Link tab, select another link. If the model name or something else first shows up in the Link Part box, clear it before selecting the link. In contrast to a Span Request, a Link Request follows one specified link as it moves around the chain loop and reports results as a function of time. Hit Next.

Creating the Chain Hit Finish on the next form.

Creating a Coupler We will now create a coupler between the driven sprocket and the tool table to provide a simple representation of a gearing system. Since we cannot currently connect a coupler to Machinery sprocket, we will connect via the revolute point on the dummy part fake, which is fixed to the driven sprocket.

Deactivate the Imposed Motion First deactivate the imposed motion on the translational joint on the tool table Right-click over the motion icon, then deactivate it as shown below. Uncheck both boxes as shown, and then hit OK.

Creating a Coupler From the Connectors tab, click on the coupler icon As instructed in the Adams message window, select the driver joint by hovering over the driven sprocket, right-click, select JOINT_32, and then hit OK. As instructed in the Adams message window, select the coupled joint by hovering over translational joint icon on the tool table, and pick JOINT_30.

Creating a Coupler Now right-click over the coupler icon shown in the graphics window and select Modify Complete the form as shown and click OK.

Creating a Motion on a Revolute Joint Note: You could create a motion from the chain actuator wizard . However, if the motion is being transferred from another part, you can just create a motion on that part (which is what we are doing here). Hover over the revolute joint icon on the part drive_shaft and select JOINT_31 > Modify. Click on Impose Motion on the Modify Joint dialogue box On the Impose Motion dialogue box, click on the arrow next to Rot Z and select disp(time)=. Then enter 360d*time in the field to the right. Hit OK twice to complete the action.

Running a Simulation Go to Settings > Solver > Dynamics and verify that the HHT integrator is selected, then click Close. We are now ready to run a simulation. From the Simulate tab, click on the Simulation Control button. Complete the form as shown (0.5 seconds, 200 steps) and then click the green arrow to start the simulation. The simulation will take a few minutes to run. Go to Settings > Force Graphics and set the force and torque scales as shown and click OK.

Post Processing Click on the animation icon and then click the forward arrow Now launch the post-processor from the Results tab

Post Processing Verify that Requests is selected under Source. Then click on user defined under Filter. Open the chainsys_1 tree under Request, and select chain_1_link result. Then pick contact_force and hit Add Curves. The result is shown on the following page. Other calculated chain parameters are shown when changing Source to Objects, Result Sets, or Measures.

Post Processing

Post Processing Click Clear Plot. Now select the request chain_1_span_at_link_93 and pick component x_velocity (velocity along the direction of the chain, not the global x-direction). Then click Add Curves.

Replace Motion on Driveshaft with Chain Actuator Optional Section Replace Motion on Driveshaft with Chain Actuator

Optional – Replace Motion on Driveshaft with Chain Actuator In this example, we applied the motion to the driveshaft, which was fixed to the driven gear. Another approach would be to constrain the driveshaft with a fixed joint (which would in effect make it a motor housing) and then use a Chain Actuator to apply motion at the driven gear. We will now modify the model to this configuration. Hover over the revolute joint on the driveshaft, and select Joint: JOINT_31 > Modify. Then change the joint Type to Fixed. Then hit OK.

Optional – Replace Motion on Driveshaft with Chain Actuator In the model browser (under Chain Systems > chainsys_1), right-click on sprocketset_1, and select Modify. Select Yes when the following message appears Close the message window when it appears. Hit Next on the first sprocket wizard form. Hit Next on the Method form. Hit Next on the Geometry-Sprocket form. Hit Next on the Material-Sprocket form.

Optional – Replace Motion on Driveshaft with Chain Actuator The Connection-Sprocket form now appears. On the sprocket1 tab, change Fixed to Rotational. Then hit Next. Hit Next for the Output-Sprocket form. Hit Next for the Completion-Sprocket form. On the Geometry-Guide form, check the field Start Angle. Currently there is a bug causing the previously entered value to not be retained. If the field is blank, enter 135. Then hit Next.

Optional – Replace Motion on Driveshaft with Chain Actuator Hit Next on the Material-Guide form. Hit Finish on the Completion form. This completes the sprocket creation. From the Machinery tab, click on the chain creation icon On the first wizard form, right click in the Name field and select sprocket_set > guesses > sprocketset_1. Then hit Next. Hit Next on the Method form. Hit Next on the Compliance form. Hit Next on the Geometry form. Hit Next on the Mass form.

Optional – Replace Motion on Driveshaft with Chain Actuator On the Wrapping Order form, enter the wrapping order as you did previously (see below) and hit Next. Respond Yes to the question about continuing the chain wrapping.

Optional – Replace Motion on Driveshaft with Chain Actuator Complete the Output Request form as previously, and then hit Next.

Optional – Replace Motion on Driveshaft with Chain Actuator Hit Finish on the Completion form. This completes the chain creation. On the Machinery tab, click on the Chain Actuator icon. On the first wizard form, right-click in the Name field and select sprocket_set > guesses > sprocketset_1. In the Sprocket field, right click and select All > guesses > sprocketset_1_driver. Then hit Next.

Optional – Replace Motion on Driveshaft with Chain Actuator On the Type form, select Motion. Then hit Next. On the Function form, enter -360d in the User Entered Func field. Note: Adams is expecting a velocity input here, not a displacement input. Hit Next.

Optional – Replace Motion on Driveshaft with Chain Actuator On the Output form, verify all boxes are checked, and then hit Next. On the Completion form, hit Finish.

Optional – Replace Motion on Driveshaft with Chain Actuator Now rerun a 0.5 second, 200 step simulation View results in the Post-processor