1 Simple Pendulum Estimated time required: 20 min GUI familiarity level required: Lower MSC.ADAMS 2005 r2

2 1.Start ADAMS 2.Manipulate the grid spacing 3.Add a rigid part & cylinder geometry 4.Rename a part 5.Change appearance (color & size) 6.Set mass properties 7.Rotate a part about the global Z-axis 8.Add a revolute joint 9.Rotate your view 10.Zoom In/Out 11.Set initial velocity of a part 12.Verify your model 13.Measure joint forces 14.Run simulations 15.Analyze the data in the Post Processor Topics Covered If you have any difficulties, import the “Pendulum_complete.cmd” file and proceed from pg 17 In this tutorial, you will learn how to:

3 AB is a uniform bar with a mass of 2 kg and a length of 450mm. Bar AB swings in a vertical plane about the pivot at A. The angular velocity (theta dot) = 3 rad/s when (theta) = 30 degrees. Compute the force supported by the pin at A at that instant. This problem is asking for the force supported by the pivot A at an instant when the 2 kg bar is 30 degrees from the horizontal and has an angular velocity of 3 radians per second. We will use ADAMS to create a model with the given conditions and obtain the data needed. Simple Pendulum

4 If you are successful, you should end up with a simple pendulum model that swings due to gravity and initial position offset from static equilibrium. That allows you to determine the angular displacement and velocity of the body in the pivot (revolute joint) at any point in time. What You Should Accomplish

5 Open ADAMS: Start  All Programs  MSC.Software  MSC.ADAMS 2005 r2  AView  ADAMS-View Start ADAMS/View Note: It’s normal to wait several moments for the application to start

6 Getting Started: a.Under the heading "How would you like to proceed", select the Create a new model radio button. b.Choose a Location to save your files c.Set Model Name as model_1 (default) d.Verify the Gravity text field is set to Earth Normal (-Global Y). e.Verify that the Units text field is set to MMKS - mm,kg,N,s,deg. f.Select OK. Create New Model a e d c b f

7 To edit the grid size: a.Click Settings menu, select Working Grid… The Working Grid Settings window will appear b.Change the Spacing text fields in X and Y to (25mm) c.Click OK a c b Change Working Grid Settings Note: you should see a denser set of dots on your screen

8 a.Click on the View menu, select Coordinate Window b.Right-click Rigid Body tool stack. Select Cylinder tool c.Turn on the Length check box, enter 450mm in the text field below. d.Turn on the Radius check box, enter 20mm e.Left-click once, on your Working grid, at the point (-225,0,0) to select the starting point and then click right of this point, in the Global X-axis to describe direction. b c d e Create Rigid Body & Cylinder Geometry a Note: that you will have to change the units from cm to mm when entering the dimensions. ADAMS keeps the defaults even if previously specified

9 Rename the Part a.Right-click on the part, select Part:PART_2  Rename The Rename window will appear b.Rename PART_2 to what you would like, in this case chose “cylinder” (i.e..model_1.cylinder) c.Click OK a b c

10 Change Size and Color a.Right-click on the cylinder close to the center. Select Marker: cm  Appearance. b.Right-click in the Color text field, then click on Color  Guesses  Yellow (you may chose a different color). Note: use a bright color to see against the black background c.Select Icon Scale from pull down menu d.Enter 2 in the text field. e.Click OK. a b c e d Note: the cylinder’s center on mass marker is now larger and a different color

11 Set the mass of the cylinder to 2kg a.Right-click on the cylinder, select Part: cylinder  Modify b.Select User Input, from Define Mass By pull down menu c.In the Mass text field enter 2.0 d.Manually override the inertias using the formula Ixx=Iyy=. Set Ixx=(1/12*2*450**2), Iyy=(1/12*2*450**2), and Izz=0 e.Input cm in text fields for Center of Mass Marker and Inertia Reference Marker f.Click OK. a f d d d c b Set Mass Properties e Note: By default. ADAMS calculates mass and inertia properties for a part based on a density value and the volume of the geometry associate with the part. These values can be overridden by you. There is no visual change

12 To set the angle of the bar at 30 degrees a.Click on cylinder. b.Click on Position tool in the Toolbox. c.Enter 30 in the Angle text field. d.Click on the clockwise arrow once. b c d a Rotate Part about Global Z axis Note: The pivot is automatically set at the origin

13 a.Right-click on Joint tool stack in the Main Toolbox, select Joint: Revolute tool. b.Set the Construction option menu to 1 Location and Normal to Grid. c.Left-click on the marker cylinder.MARKER_1 at the left end of the cylinder. d.A joint between the cylinder and the ground is created at that location. b c d a Add a Revolute Joint

14 Rotate your View & Zoom In/Out Right-click on the working grid and select Rotate XY or click on the working grid and press Click and hold the left mouse button. Moving the mouse will now rotate the part. To exit, release mouse button To zoom in/out click on the working grid and press  click and hold left the mouse button. Move the mouse up to zoom in and down to zoom out Release mouse button to exit. Note: Y-axis is the axis we are rotating about, which is the same as the global Z-axis which is shown in the bottom left corner of the working grid

15 a.Right-click on the cylinder, select Part: cylinder  Modify. b.Select Velocity Initial Conditions from Category pull down menu c.Under the heading Angular velocity about, select the Part CM radio button. d.Below that, turn on the Y axis checkbox and enter (3rad), for 3.0 radians per second, in the text field that appears next to it. e.Click on Apply f.Click on Ok to close window. a b c d e f Set Initial Velocity

16 a.In the lower right corner of the modeling window, right-click on the Information icon. b.Click on the Verification icon. The Info Window appears c.After seeing that the model has verified successfully, d.click on the Close button a b c d Verify Your Model Note: The model verification step is one way to find errors in the model definition. ADAMS checks for error conditions such as misaligned joints, unconstrained parts, or massless parts in dynamic systems, and alerts you to other possible problems in the model.

17 To measure the force on the joint: a.Right-click on the revolute joint at the upper left end of the bar, Select Joint:JOINT_1  Measure. The Joint Measure dialog box opens. b.Select Force from the Characteristic pull down menu c.Select mag (magnitude) radio button for Component d.Click OK. A graph window named JOINT_1_MEA_1 appears. This is where the reaction force will be plotted during the simulation and animation. a b c d Measure Joint Forces Note: you can create measures before, during and after a simulation

18 This is what your screen should look like when your model is completeModel

19 How to simulate the model: a.Click on the Simulation tool in the Toolbox. b.Enter 0.5 for End Time and 50 for Steps. c.Click on the Play button. You should see the bar swing about the pivot and corresponding data should be plotted on the JOINT_1_MEA_1 graph. d.When the simulation ends, click on the Reset button. e.Right-click on a blank area inside the small plot window, select Plot: scht1  Transfer to Full Plot. a b d c b Run a Simulation e

20 ADAMS Post Processor should open a.Select the Plot Tracking tool. b.Since we know the initial conditions are met at the start of the simulation, move the cursor over the starting point of the plot. c.At the top of the window, X will be displayed as 0 and Y, which is the force on the pivot, will be displayed. Compare it to the results given in the Solution section of this Tutorial. d.To return to the modeling window, go to the File pull-down menu and select Close Plot Window or press F8 or click on the Return to modeling environment button d c b aAnalysis

21 Theoretical Solution ADAMS solutionResults

22 1.Start ADAMS 2.Manipulate the grid spacing 3.Add a rigid part & cylinder geometry 4.Rename a part 5.Change appearance (color & size) 6.Set mass properties 7.Rotate a part about the global Z-axis 8.Add a revolute joint 9.Rotate your view 10.Zoom In/Out 11.Set initial velocity of a part 12.Verify your model 13.Measure joint forces 14.Run simulations 15.Analyze the data in the Post Processor Topics Covered In this tutorial you learned how to:

23 Make sure the units are correctly set. Make sure gravity is on and in the proper direction and set to the proper number. Make sure the revolute joint is in the correct direction. Check dimensions of your parts to make sure they are correct. Check mass properties to make sure they are correct. Check orientation of the part to make sure it is correct. Make sure your model verification is successful Make sure the measures are set properly. Make sure the plot is displaying the correct set of results. Best Practices

24 Further Analysis (Optional) Can you solve this problem for Static Equilibrium a.click the simulation tool b.in the simulation option menu select Static c.measure the joint force  you should get d.Or press the Static Equilibrium button Can this problem be done in more/less steps? -check the effect on plots and animation a b c d