Aaron Klapheck's Website

The very first step to take is to make sure all the numbers entered have the proper units.
The Numbers and Units window can be opened from the View menu located on the menu bar.

Choose English (Pounds) as the standard so that length will be in inches but then click the button More Choices.
For Rot. Velocity choose Rev/min.

To turn off the simulated gravity go to the World menu and then hit Gravity....
Then select the none ratio button.

Draw two rods by using the Rectangle tool on the left side menu.

Specify the geometry of each shape by typing ctrl+k after selecting each shape.

The next step consists of placing one Point element and one pin joint the smaller bar.
Then place two point elements on the larger bar at each end.
The point elements and joint must be placed on the outer edges of both bars.
This is because the geometry of these parts can only be selected from their edges, not from point to point.
So if the diagram calls for two points to be a give distance from each other the only way to specify
this distance is to make the geometry of the part the distance and placed the points on the ends of the part.

Select a Point element on the larger bar and the one on the smaller bar and select Join from the menu on the left side.

Select the Slot joint on the left side menu and place it on the upper left corner of the smaller bar.
Make sure the cross hairs appear as depicted in the picture to the left.
These cross hairs indicate where the slot joint will be placed.
A Pin joint element will appear after left-clicking, delete this joint.

After deleting the pin joint, select the free point element on the bar and the slot, then hit the Join button.

Place the motor on the pin joint of the smaller bar and double-click it.
A window will open where we can put he rotational velocity.
The velocity given is 1,000 rpm CW, but all measurements are CCW so a negative is placed in front of the numbers.

If the simulation is ran at this time it will appear jumpy because of the high rpm's selected.
To solve this problem more frames per second need to be displayed.
This can be done through selecting the World menu followed by Accuracy....

The accuracy can be specified in the Simulation Accuracy window.
Instead of using the automatic Animation Step, select the ratio button that allows you to input 0.0001s.

Select the point connecting the rod to the slot then select Measure then Velocity from the menu bar.
Repeat this twice until two you get the picture directly to the left.

For one of the velocity mini windows click the white arrow located in the upper left of each mini window.
Then expand this window so the graph will be visible.

With the same point still selected click Measure then Position.

Next select the rod and select Measure, Velocity, then Rotation Graph from the menu bar.

With the rod still selected click the following: Measure, Velocity, then All

For four of the windows shown there is extra information given that we don't need.
For every piece of information that is not needed click the box (all boxes are located underneath the white arrow for each little window).
Click all the boxes except Vy, y, and Vphi.

Select the joint connecting the rod to the slot and make the following selections: Define, Vectors, then Velocity.
With this joint still selected click the following: Define, Vectors, then Acceleration.

Select the joint connecting both rods and make the following selections: Define, Vectors, then Velocity.
With this joint still selected click the following: Define, Vectors, then Acceleration.

Make the following selections Define followed by Vector Lengths.
The screen on the right will appear. Input the following:
for velocity put in 1.000e-004, and for acceleration put in 3.000e-006.

This is the result when played.

The motion of the piston

The result can be seen in the video to the left.
Although only a few rotations are captured, the Working Model file can be
downloaded from the Dynamics of Machinery page where it may be played for an extended period of time.

The solution to the problem when theta is zero is given to the left.
The velocity of the collar in the y direction is -0.111 in/s up.
The angular velocity of bar BD is 375 rev/min CCW.

The solution to the problem when theta is 90 is given to the left.
This value is close to the value given in the back of the book which is 12.25 in/s up.
This value is nearly identical to the answer in the back of the book of 4.38 rad/s CW.