Bevel Gear detailed analysis with different mesh sizes (6mm, 5mm & 4mm) using Ansys.

Objective: Bevel Gear detailed analysis with different mesh sizes (6mm, 5mm & 4mm) using Ansys.

Theory:

1. Grid Dependency Test: It is also known as mesh convergence test should mean computing the solution on successively finer grids. The difference between the two refinements is usually taken as a measure of the accuracy of the coarser of the two.

The most fundamental method of checking the mesh quality is to refine a mesh until a critical result such as Equivalent stress does not change significantly with each refinement (i.e. it converges). This is the Grid dependency test, where, analysis begins with a coarse mesh and it tends fine mesh for each run until the results do not change significantly and depend on the grid size anymore.

As the grid or mesh size approaches zero, the approximate solution is almost equal to the actual solution. The aim of this test is to find the optimum mesh size for the solution, where it will consume a lot of computing effort and time. There are different mesh refinement techniques that are used which has advantages and disadvantages and some depend on the experience and technical expertise of the FEA analyst.

These techniques include- Reducing the element size, Increasing the element order, Global Adaptive mesh refinement, local adaptive mesh refinement, manually adjusting the mesh, Time adaptive mesh refinement, wavelength adaptive mesh refinement, etc.

Bevel Gear CAD Model:

It is always important to remove the unnecessary part to reduce the time to run the simulation.

Material Assigned:

Structural Steel:

General Set up:

Augmented Lagrange: As soon as gears come in contact part does not vibrate or move off from its location. It increases stiffness and reduces penetration and chattering.

Analysis Setting:

Joint Load

Rotation on small gear:

Moment acting on big gear:

Meshing:

Face sizing because we want to get the accurate results so reduced the mesh size at the contact surfaces.

Size: 1.75 mm

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Simulation results

Case 1: 6mm

Total Deformation:

Equivalent Stress GIF:

Stress Graph

Equivalent Strain:

Strain Graph

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Case 2: 5mm

Total Deformation

Equivalent Stress:

Strain:

Strain Graph:

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Case 3: 4mm

Equivalent Stress:

Equivalent Strain:

Conclusion:

Mesh size	Total Deformation	Max Stress	Max Strain
	mm	Mpa	mm/mm
6mm	47.8	5.39	3.318e-5
5mm	47.8	5.19	3.318e-5
4mm	47.8	5.57	3.614e-5

As expected from grid dependency test we can see that there is a change in stress and strain values. Values increased as the mesh gets finer and we can observe that model can be excepted because max total deformation is constant and the strain produced is also very small. So through the grid dependency test, we can better judge the model for acceptance in real-life scenarios.