Transcript Rename the Part - MSC SimCompanion

Simple Pendulum
Estimated time required: 20 min
GUI familiarity level required: Lower
MSC.ADAMS 2005 r2
1
Topics Covered
In this tutorial, you will learn how to:
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
If you have any difficulties, import the “Pendulum_complete.cmd” file and proceed from pg 17
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Simple Pendulum
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.
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What You Should Accomplish
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.
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Start ADAMS/View
Open ADAMS:
Start  All Programs  MSC.Software  MSC.ADAMS 2005 r2  AView ADAMS-View
Note: It’s normal to wait several moments for the application to start
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Create New Model
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.
a
b
c
d
e
f
6
Change Working Grid Settings
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
b
c
Note: you should see a denser set of dots on your screen
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Create Rigid Body & Cylinder Geometry
a.
b.
c.
d.
e.
Click on the View menu, select Coordinate Window
Right-click Rigid Body tool stack. Select Cylinder tool
Turn on the Length check box, enter 450mm in the text field below.
Turn on the Radius check box, enter 20mm
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
e
a
c
d
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
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Rename the Part
a.
Right-click on the part, select Part:PART_2  Rename
a
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
b
c
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Change Size and Color
a.
Right-click on the cylinder close to
the center. Select Marker: cm 
Appearance.
a
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
b
c.
Select Icon Scale from pull down menu
d.
Enter 2 in the text field.
e.
Click OK.
d
c
Note: the cylinder’s center on mass marker is now larger and a
different color
e
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Set Mass Properties
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
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2
d.
Manually override the inertias using the formula Ixx=Iyy= 12 ml . 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.
b
c
a
d
d
d
e
f
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
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Rotate Part about Global Z axis
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
a
d
c
Note: The pivot is automatically set at the origin
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Add a Revolute Joint
a.
b.
c.
d.
Right-click on Joint tool stack in the Main Toolbox, select Joint: Revolute tool.
Set the Construction option menu to 1 Location and Normal to Grid.
Left-click on the marker cylinder.MARKER_1 at the left end of the cylinder.
A joint between the cylinder and the ground is created at that location.
a
c
d
b
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Rotate your View & Zoom In/Out
Right-click on the working grid and select Rotate XY <r> or click on the working grid and press <r>
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 <z>  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
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Set Initial Velocity
a.
Right-click on the cylinder, select
Part: cylinder  Modify.
a
b
b.
c.
d.
e.
f.
Under the heading Angular velocity about,
select the Part CM radio button.
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.
Click on Apply
Click on Ok to close window.
Select Velocity Initial Conditions from
Category pull down menu
c
d
e
f
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Verify Your Model
a.
b.
In the lower right corner of the modeling window, right-click on the Information icon.
Click on the Verification icon.
a
b
c.
d.
The Info Window appears
After seeing that the model has verified successfully,
click on the Close button
d
c
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.
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Measure Joint Forces
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.
a
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.
b
c
A graph window named JOINT_1_MEA_1 appears.
This is where the reaction force will be plotted
during the simulation and animation.
Note: you can create measures before, during and after a simulation
d
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Model
This is what your screen should look like when
your model is complete
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Run a Simulation
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.
a
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.
c
d
e.
Right-click on a blank area inside the small plot window, select
Plot: scht1  Transfer to Full Plot.
b
b
e
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Analysis
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
a
d
c
b
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Results
Theoretical Solution
ADAMS solution
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Topics Covered
In this tutorial you learned how to:
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
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Best Practices
•
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.
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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 19.61
d.
Or press the Static Equilibrium button
a
c
b
d
Can this problem be done in more/less steps?
-check the effect on plots and animation
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