Week 7-Long Piston With Cam

OBJECTIVE:

• To perform a transient analysis on a piston and cam mechanism model.
• To run the analysis with Frictionless contact, Frictional with 0.1 and 0.2 as the frictional contact for a total of 3 cases.

Required Results and Deliverables:

• Equivalent Stress, Directional Deformation and Equivalent Elastic Strain and compare them for all the three cases. Give an inference as to why the results vary between cases.

Procedure:

Step 1: Engineering Data

• For this analysis we will be using Static Structural as material which can be found in engineering data.

Step 2: Geometry

• Right click on geometry and Import the Long_piston_cam_Skill_Lync.x_t extension file
• Rename the Static Structural tab as Long Piston with cam.
• Update the Static Structural tab and proceed to model.

Step 3: Model and Meshing

• Open Model and under geometry assign names according to convenience for understanding.
• Assign rigid as stiffnes behaviour to both the bodies (barrel and barrel cam). This way the solver will consider them as point masses.

Step 4: Connections

• Contacts:- Define the Buckle and clip faces as frictional type and assign a Frictionless contact, frictional contact with coefficient of 0.1,0.2 for CASE 1,2 and 3 respectively. No change in rest settings.

Step 5: Setup

• In analysis settings we are going to simulate this case in 9 steps.
• Enter 9 as the number of steps and select all the steps simultaneously and switch on the large deflection in solver controls.
• Turn on auto time stepping defined by time,0.1 as initial time step,5e-02 as minimum time step and 0.2 as maximum for first step and 0.3 for steps 2-9.
• In nonlinear controls change stabilization to constant with energy dissipation ratio of 0.1 and activation for first substep as Yes. Change solver type as program controlled.
• Insert rotational joint type to defined revolute joint.(Ground to Barrel Cam)

Step 6: Solution

• Insert results for Equivalent Stress, Equivalent Strain, Total Deformation, Directional deformation for geometry in focus.
• Parametric study has been carried out for cases with frictional coefficient of 0.1 and 0.2.

Results:

CASE#	Contact Type	Equivalent Stress	Directional Deformation	Equivalent Elastic Strain
Units		MPa	mm	mm/mm
Case 1	Frictionless	410.17	10.436	0.0020668
Case 2	Frictional- 0.1	510.02	10.476	0.0026446
Case 3	Frictional- 0.2	725.01	10.539	0.0037472

Inference: As we assign a frictional contact to the contact surface in focus we see that stress increase due to frictional resistance between contacts. As a result the Equivalent stress values are 410.17 Mpa, 510.02 Mpa and 725.01 Mpa for frictionless, Frictional conatct with 0.1, Frictional conatct with 0.2 respectively. A similar trend is seen in equivalent strain. The directional deformation is not much affected and stays between 5% of values in case of frictionless motion.