Week 8 - Universal Joint
OBJECTIVE: The main objective of this challenge is to perform a Transient structural Analysis on a double universal joint with a spring using three different materials such as Structural Steel, Stainless Steel and Titanium alloy. And to obtain the Equivalent stress and total deformation for all the three cases and compare them.
PROCEDURE:
1. Open the ANSYS Workbench software. Under the Analysis system select the Transient structural and wait for few seconds to pop up the window, which contains Engineering data, Geometry, Model, setup, Solution and Results.
2.Under geometry import the Long Universal Joint.
3.Update the model by right click and edit the Model for Preprocessing.
4. Wait for few seconds and ANSYS Mechanical will open
5. Assign the material to the model. Default we have structural steel. We have to change the material of springs alone and assign three different type of material for three cases. first assign structural steel, then Stainless Steel and Titanium alloy.
6. In this case we are not concentrated on the contacts. So delete the contacts and insert joints.
a) Fixed Joint: For the tip of the spring we have to insert fixed joint and select the face . Use body to ground option.
b) Revoiute joint: Insert a revolute joint for the gear part(Driver Yoke) and select the face as shown below. Connection type as body to ground. Make sure that the rotation axis must be oriented correctly.
c) Revoiute joint: Insert a revolute joint for the spring part(Driven Yoke) and select the face as shown below. Connection type as body to ground. Make sure that the rotation axis must be oriented correctly.
d) Revoiute joint:
In universal joint we have 8 pins, that connect the driver yoke to driven yoke through a cross trunion. So we have to make the pins as revolute joint. Here we have shown one pin as example. Follow the same method for remaining pins.
Insert a revolute joint to the pin of gear part(Driver Yoke) and select the face as shown below. Connection type as body to body. Make sure that the rotation axis must be oriented correctly.
8. In ANSYS automatic mesh will be performed with Default mesh size, so assign a element size of 3mm and select the sizing option and select the faces as shown below and assign the element size as 2mm. Right click on mesh and insert a method, Select the method type as tetrahedrons and select all bodies
9. Analysis settings Change no. of steps as 5, Weak spring as program controlled, large deflection on, output controls all as yes, auto time step off and select all steps and provide the time step as 0.1s.
11. Joint Load for the gear part is defined by inserting a joint load and change the type as rotation, (Z) select the face as shown below for scope and magnitude of 0,-30,-60,-90,-120,-150.
12. Now request for the outputs such as equivalent stress, equivalent elastic strain, Total deformation.
13. SOLVE the solution and we can see the simulation run under soluion information.
SIMULATION RESULT:
CASE-1: Structural Steel Material
Total Deformation
Equivalent stress
\
Case 2 : Stainless Steel
Total deformation
Equivalent Stress
Case 3 Titanium Alloy
Total Deformation:
Equivalent Stress
COmparision of Results
| Case | Total Deformation (mm) | Equivalent Stress(MPa) |
| Structural Steel | 38.637 | 1501.2 |
| Stainless Steel | 38.637 | 1531.6 |
| Titanium Alloy | 38.637 | 730.11 |
CONCLUSION:
From the above result we can conclude that the Maximum equivalent stress of 1531.6MPa is experienced at Stainless steel, and minimum equivalent stress of 730.11MPa is experienced at Titanium alloy, Moderate equivalent stress of 1501.2 is experienced at Structural steel. The total deformation of 38.637mm in all the cases remains same. So we conclude that the changing of different material to a model will not effect the total deformation and it remains same for all the cases.