Week 7-Long Piston With Cam

OBJECTIVE

To perform a transient analysis on a piston and cam mechanism model

Run the analysis for a total 2 cases

Case 1  Frictionless contact

Case 2  Frictional with 0.1 as the frictional contact

Case 3  Frictional with 0.2 as the frictional contact

PRODECURE

Create transient structural analysis and in engineering data select the material structural steel 

Structural Steel

Import the geometry and check in spaceclaim for any irregularties

Then open ansys mechanical and rename the geometry as Barrel ,Barrel_cam and Cam_follower then assign the structural steel material

                                                             

CONTACTS  

Two contacts created in the whole setup with frictionless or  frictional type with friction coefficient of 0.1 and 0.2 and interface treatment is set to Add offset , Ramped effects

CASE 1  Frictionless contact

CASE 2  Frictional with 0.1 as the frictional contact

CASE 3  Frictional with 0.2 as the frictional contact

Contact  Cam_Follower to Barrel

                                                 

Contact Cam_Follower to Barrel_Cam

                                                

Joints   Three joints created in whole geometry

Fixed Ground To Barrel

                                                                   

Revolute    Ground to Barrel_cam

                                                                   

Translational  Barrel to Cam_follower

                                    

Mesh    Face Sizing  Option use for meshing  3mm element size 

                                                

                                                     

Analysis Settings

The simulation runs for 9 steps so that the number of steps is set as 9

In the first step large deflection set to on and defined by time step  set to 0.1s  Minimum time step set to 5e-2s and Maximum time step set to 0.2s and stabilization set to constant method to energy and energy dissipation ratio to 0.1 activation for first step to yes. In output control set all output to yes except contact miscellaneous. 

 

Second step to nine step large deflection set to on and defined time .Carry over time set to on Initial time step set to 0.1s  Minimum time step set to 5e-2s and maximum time step to 0.3s and stabilzation set to constant method to energy and energy dissipation ratio to 0.1 activation for first step to yes .In output control set all output to yes excpt contact miscellaneous.

Joint Rotation Cam is provided a rotation of 270 degrees

                                                       

                                                        

Run the simulation and results obtained

Result  The analysis runs successfully and results obtained

Case 1   Frictionless Contact 

Equivalent Stress Max - 1756.6 Mpa

                                                     

                                                     

Total Deformation  Max - 35.921mm

                                                        

                                                        

Directional  Deformation Max - 11.096 mm

                                                         

                                                         

Equivalent Elastic Strain Max - 0.0088296 mm/mm

                                                          

                                                          

Case 2 Frictional with 0.1 as the frictional contact

Equivalent Stress Max - 1849.1 Mpa

                                                                                    

                                                       

Total Deformation  Max - 35.921mm

                                                         

                                                         

Directional Deformation Max - 11.134 mm

                                                              

                                                              

Equivalent Elastic Strain Max - 0.0095993 mm/mm

                                                        

                                                        

Case 3 Frictional with 0.2 as the frictional contact

Equivalent Stress Max - 2339.1Mpa

                                                 

                                                 

Total Deformation  Max - 35.921mm

                                                        

                                                       

Directional Deformation Max - 11.235mm

                                                             

                                                            

Equivalent Elastic Strain Max - 0.012101 mm/mm

                                                                

                                                               

CONCLUSION

 INTERFACE

• Equivalent  Stress - Stress keeps on increasing as we increase the friction coefficient values .As the friction coefficient calue increases it resists more the movement of the follower and thus stress develops at the stem of the follower 
• Directional Deformation  It  is increasing slightly with increasing friction coefficent value
• Equivalent Elastic Strain  Also because of the same reason as equivalent stress , Equiavalent strain also increases due to more resistance offered.