Week 7-Long Piston With Cam
SIMULATION OF LONG PISTON WITH CAM
OBJECTIVE
To perform transient analysis on a Piston and Cam mechanism model with three different contacts as mentioned in the below cases
Case 1: Frictionless contact
Case 2: Frictional contact with 0.1 as the Friction Co-efficient
Case 3: Frictional contact with 0.2 as the Friction Co-efficient
Compare the results of Equivalent Stress, Directional Deformation and Equivalent Elastic Strain and provide conclusion
MODEL SETUP
The 3D model of the setup is imported into ANSYS Space Claim. Check for any abnormalities in the Geometry.
MATERIAL ASSINGMENT:
- Structural Steel is assigned for this model
The properties of the materials used are shown below
- Structural Steel :
MODEL SETUP:
After importing the Geometry, rename the Parts and assign respective materials.
For the Barrel and the Barrel Cam, the Stiffness behaviour is assigned as Rigid.
CONTACTS DEFINITION:
We need to define two contact regions for this model. The contact regions are selected between
- The barrel and the Piston of the follower
- The face of the follower and the Barrel Cam profile
Case 1: Frictionless contact is selected between these contact regions.
Case 2: Frictional contact with frictional co-efficient 0.1 is selected between these contact regions
Case 3: Frictional contact with frictional co-efficient 0.2 is selected between these contact regions
The settings are as shown above
JOINT DEFINITION:
We need to define joints for the model
- A fixed support for the barrel:
- A Revolute joint is assigned for the Barrel Cam :
Make sure the reference co-ordinate system assigned to the joint is along the Z axis.
- A Translational Body-Body joint is assigned to the Piston rod of the follower
Make sure the reference co-ordinate system assigned to the joint is along the X axis.
MESHING:
The meshing is done as follows,
- A face sizing of element size 3 mm is selected on the
- Surface of the follower
- The profile of the Barrel Cam
MESH QUALITY:
ANALYSIS SETTINGS:
Now, the simulation is run for 9 steps. The following settings are modified
Auto Time stepping is set to ON and Time step values are assigned as shown below.
Solver Type is set to Direct
Weak springs are set to Program Controlled
The Large deflection is set to ON.
Other settings are as shown below
BOUNDARY CONDITIONS:
The boundary condition for this model are
- A Revolute Joint load is assigned to the Barrel Cam:
RESULTS:
ANIMATION :
Case 1: Frictionless contact for the Contact regions
- Equivalent Stress
- Directional Deformation
- Equivalent Elastic Strain
Case 2: Frictional contact with 0.1 as the Friction Co-efficient for the Contact regions
- Equivalent Stress
- Directional Deformation
- Equivalent Elastic Strain
Case 3: Frictional contact with 0.2 as the Friction Co-efficient for the Contact regions
- Equivalent Stress
- Directional Deformation
- Equivalent Elastic Strain
CONCLUSION:
From the results, it can be inferred that
- Directional Deformation remains almost same for Case 1 and Case 2. But, when Friction Co-efficient is changed to 0.2, there is a significant variation in the Deformation and so Frictional Co-efficient directly impacts the directional deformation.
- Equivalent stress increases while Frictional Co-efficient between the contact regions is increased. Equivalent stress changes, when friction between the contacts changes and is directly proportional to the Friction Co-efficient, as more stress will be induced for overcoming the friction.
- Equivalent strain also changes with the Friction Co-efficient and it is directly proportional to it, because stress induced is more, which is directly proportional to the strain
From the above results, Equivalent Stress, Directional Deformation and Equivalent Elastic Strain is directly proportional to the Friction Co-efficient.
The simulation files are attached below