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Mechanism Analysis in Pro/E

MAE 4344Mechanical & Aerospace Engineering

University of Texas at ArlingtonMukund Narasimhan & Kent L Lawrence

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Link Specs

Each link is 0.5 inch thick and 1.0 inchwide.

The pin holes are 0.5 inch in diameter, and

link lengths are between pin hole centers.

The material for each is steel.

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Joint definitions

1>

2 >

3 >

4 >

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Motion

The 5 inch input link rotates at a constantangular speed of 1800 rpm = 10,800 deg/sec

in a CCW sense.

Find the connection forces at each joint for

one revolution of the mechanism.

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GROUND BLOCK

Change units from Inch Lbm Sec to Inch Lbf Sec for ALL parts.

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LINK 1

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LINK 2

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LINK 3

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File > Open > Select link1.prt

Define Materials

for all Parts >>

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Edit > Setup > Material > Define > (Enter material name) Steel > Accept

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A notepad opens up > Enter MASS_DENSITY = 0.7331E-03 > File

> Save as > Steel.mat > Exit (First toggle on all files not TXT.)

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Assign > From Part > STEEL > Accept > Done

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File > Open > Select link2.prt

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Edit > Setup > Material > Assign > From Part > STEEL > Done

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File > Open > Select link3.prt

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Edit > Setup > Material > Assign > From Part > STEEL > Done

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FILE > NEW > ASSEMBLY > NAME FourBar > OK

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SET UNITS FOR ASSEMBLY Edit > Setup > Units > Select Inch Pound Second

> Set > Select the 1st option > Ok > Close > Done

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Click on Add Component to the assembly icon

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Select block1.prt > Open

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Click on the icon Assemble Component at default location

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Click on Ok

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Click on Add Component to the assembly > link1.prt > Open

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Click on CONNECT Tab at top-right

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Keep the default Pin joint > Axis Alignment > Select A1 and A3 axes (Yellow Arrows)

Translation > Select the surfaces as shown (Green Arrows)

Back

Surface

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Click on Move Tab and rotate the link to required position

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Click on Add Component to the assembly > link2.prt > Open

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Keep the default Pin joint > Axis Alignment > Select A4 and A3 axes (Yellow Arrows)

Translation > Select the surfaces as shown (Green Arrows)

Back surface

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Select block1.prt > OpenInsert Base Block Again

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Select link3.prt > Open

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Keep the default Pin joint > Axis Alignment > Select A4 and A3 axes (Yellow Arrows)

Translation > Select the surfaces as shown (blue Arrows)

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Click on ok. Add one more Connection > Pin joint

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Align the A4 with A1 and for Translation Select the surfaces as

indicated by green arrows.

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Mechanism Mode Select Mechanism option from the menu bar.

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To define the driver, select the Define Servo Motors icon.

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Click onNewbutton to define the parameters of the servo motor.

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Select the JOINT 1 axis indicated by orange colored arrow to be

the servo motor axis. > Enter 10800 > OK > Close

1>

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Click on Define Initial Conditions to set the initial parameters.

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SelectNew to define new conditions.

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Define any initial desired parameters.

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Click on Run Analysis icon as indicated

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Click onNew.1. Do KINEMATIC Analysis First

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Click on Run to compute the results > OK > Close

ote that the initial confi uration is the current osition.

Set Motion Start, End time and Interval.

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Select Replay previously run analyses to display the motion.

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Click on Play current result set to run the analysis.

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Click theplay option to play the animation.

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Click on create new measure.

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Use default name measure1. Select Type of parameter > Position >

select the JOINT 3 axis > OK.

3 >

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Select the Graph icon at the Top.

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This gives the position/displacement of joint shown in red.

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Graphs can be obtained for various options shown.

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Click on the icon shown to generate dynamic analysis of this Mechanism

2. Do the DYNAMIC Analysis Next

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Click on Analysis Icon > New > Select Type Dynamic > Run > OK > Close

Note that the initial condition is the current state.

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Select Generate Measure Results of Analyses to obtain the value of

forces on the selected joints.

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Select Connection Reactions to obtain Reactions at the joints.

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Select the joint and the measure to be plotted onto the Graph.

In this case the Radial Forces are computed for all the Joints.

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Now the JOINT 2 is selected and component to be plotted

Radial Force > OK.

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Select measure2 and Analysis Definition2 > Click on the Graph

icon at the top left.

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The Graph shows the Connection Reactions at JOINT 2.

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File > Export Text

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One can also write the results into Text file. Later this can be opened in notepad

or wordpad.

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Slides 65 through 73 do the same for JOINTS1, 3, & 4.

Skip ahead to Slide 74

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Select JOINT 1 > component to be plotted Radial Force > OK

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Select measure3 and Analysis Definition2 > Click on the Graph

icon at the top left

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The Graph shows the Connection Reactions at JOINT 1.

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Select JOINT 3 > component to be plotted Radial Force > OK

3 >

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Select measure4 and Analysis Definition2 > Click on the Graph icon at the top left

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The Graph shows the Connection Reactions at JOINT 3.

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Select Fourth Joint > component to be plotted Radial Force > Ok

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Select measure5 and Analysis Definition2 > Click on the Graph icon

at the top left

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The Graph shows the Connection Reactions at JOINT 4.

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Find the torque that must be

applied by the servo motor.

Create new measure > Net load > (pick the servo motor)

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Information note:

To verify this analysis with an existing SI analysis

everything was switched to SI for the Torque calculation.

Note on previous slide that the measure units are m-N

as are the torque results on the next slide.

To verify these results, either convert your lbf-in torque to N-m

for comparison or convert units during the analysis as we did.

Servomotor Torque in m-N

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Fin