Aaron Klapheck's Website

Fist sketch the arm of the cross piece, then extrude it. Make sure that the origin is in between the two segments of the cross-piece. (in the middle of the "cup"). This will make the work done in Nastran much easier.

Create an offset plane that is 200mm away from a certain point which we will use later to make a hole.

Sketch a circle and extrude it to the surface of the cross piece.

This is the hole mentioned earlier. create this by sketching a circle and cutting the circle through both parts. After this is done save your part and open a new one.

Sketch a rectangle and revolve it around the vertical axis. (Changing the 10mm to a 9mm will make the part fit easier.).

Sketch another rectangle along the horizontal. (Again, changing the 10mm to a 9mm will make the part fit easier.).

If an assembly is made from the parts then it will look similar to the figure on the left. (Note: if 9mm were used for the T-bar then there will be small gaps where the parts connect, this is important for operation in Nastran! Otherwise parts will grind.) Close the assembly file.

Open each part separately and save it in STEP AP203 format.

Click on Display Settings

Turn the grid on, turn gravity off, and set the length to millimeters in units.

Display the edit toolbar in toolbars.

Import both parts one at a time.

Surprisingly when importing both parts they should automatically be positioned correctly. This will happen if the origin of the Rotating_Rod is centered along its axis (see the solidworks part, step 1), and the origin of the T_shape is located at its center.

copy the Rotating_Rod. Notice the copy is called Copy of Rotating_Rod.

Change the orientation of the Rotating_Rod to that shown in the picture to the left.

Change the orientation and position of the Copy of Rotating_Rod to that shown in the picture to the left.

The next series of steps will allow both Rods to rotate in place along their axis but not move from side to side. Change the view so that the cylindrical surface of the Rotating_Rod is visible. Then select Revolute Joint from the drop down menu

Select the surface of the cylinder twice (make sure to separate both points otherwise this won't work). Make sure the Split Constraint ratio button is selected then click OK.

Next we must center both coordinate point by selecting their properties from the Object Browser.

Center coordinate[6] by using the x, y, and z values shown in the picture to the left.

Center coordinate[7] by using the x, y, z, and Ry values shown in the picture to the left.

Once this is done join the constraint. (This should be the only constraint that needs the step).

Joint this coordinate in place.

The next step is to reposition the Rotating_Rod. Give it the angle as shown in the picture to the left.

Perform steps 9 through 16 for the cylindrical face of Copy of Rotating_Rod. Notice that after the final position is established that the constraint automatically joins correctly.

The next step is to place constraints on the parts where the T_shape contacts the two Rods. The first constraint will also be a Revolution Joint to joint the T_shape to the Copy of Rotating_Rod.

Place the first coordinate on the "top" face of the T_shape, and the second one on the surface of the crosspiece. (when placing the second coordinate make sure the surface of the crosspiece darkens before placing it).

Make sure the Split Constraint ratio button is selected then click OK.

Once this is done centering of both coordinates takes place using the same steps as mentioned previously. See the picture to the left for an example of the x, y, and z positions to use.

Perform steps 18 through 21 for the T_shape and Rotating_Rod connection.

To apply the angular velocity (omega) to the Copy of Rotating_Rod (Rod AC in the book) simply pace a Revolute Motor on the cylindrical surface of Rod AC.

After centering the motor it should automatically join (appear solid).

Let the angular velocity omega be equal to 90 degrees per second.

The next series of steps involve measuring the angular velocity of the Rotating_Rod. After selecting the Rotating_Rod perform the following menu selections as seen in the picture to the left.

The final result should resemble the picture to the left.

The motion of the disk

The final animation should resemble what is shown by clicking on the picture to the left.

The answer given in the back of the book is shown: omega_2 = omega_1 / cos(20 degrees). When omega_1 is equal to 90 degrees per second then omega_2 equals 95.776 degrees per second. The answer given on in the figure to the left can be seen in the lower left corner of the graph. The Nastran answer is 95.8 which matches the analytical solution exactly.