Week 2 Bevel Gear Challenge

Objective: To define what grid dependency test is and perform it on a bevel gear for mesh sizes 6, 5 and 4 and evaluate the effect on results like Von-Mises stress, Equivalent elastic strain and Total Deformation.

Grid dependency test :

• Definition:- The grid dependence test is a process used to find the optimal grid condition that has the smallest number of grids without generating a difference in the numerical results based on the evaluation of various grid conditions.
• Explanation: A solution can never be trusted unless we check whether the result depends on the grid or not, or else we have any experimental data. The output result of a coarser mesh and finer mesh can neither be same. So upto what extent, we need to vary the mesh to get the accepted level of tolerance, can be found out from grid dependency test.

Setup:

Engineering data:

Structural steel material

Geometry:

• exported igs file of bevel gear.
• Edited the model in spaceclaim by removing excess material which is not the part of analysis.

Model:

Geometry: renamed both gear to Small gear and Big gear and material is structural steel for both gears

Coordinate system: no change

Connections:

Contacts:

• frictional- small gear to big gear
• Joints: Revolute ground to small gear
• Joints 2: Revolute ground to big gear

Mesh

• Scope : geometry selected 40 faces of both gears coming in contact
• Face sizing: clicking on the box for parametric option.

Static structural:

• Analysis setting:

1. number of steps =6
2. Initial Time step= 0.2 s
3. Min time step= 0.1 s
4. Max time step = 1 s

• Joint : Rotation ground to small gear (120° with 20° gap)
• Joint: Miment ground to big gear (100 N)

Solution:

Mesh 6

• Equivalent stress

• Equivalent elastic strain

• Total deformation

Mesh 5

• Equivalent stress

• Equivalent elastic strain

• Total deformation

Mesh 4

• Equivalent stress

• Equivalent elastic strain

• Total deformation

Result: All the analysed data is in an attached excel file.

Conclusion:

As can be seen that most of the results are similar in case of Mesh 6 and Mesh 4. Hence we can conclude that the analysis can be performed at Mesh 6 and we would get the most approximate results.