Week 8 Worm Gear Challenge

1. Objective

We have to perform a transient structural analysis on a worm gear assembly. We need to cut the gear by half to bring the model within limits. Also, we need to rotate the worm so as to get to almost the end of the half cut and get results for Equivalent stress, Equivalent elastic strain and the total deformation in the model.

2. Case setup and execution

Import geometry file. Cut the gear in half using SpaceClaim to avoid excessive simulation time and keep the analysis within the prescribed limits for a student license.

Rename parts in geometry as a worm and wheel

Rename default contacts based on the definition. Change contact type to frictionless. The target body will be wheel and contact body will be worm

Include additional faces for target bodies.

Insert ground-to-wheel revolute joint by selecting the inner face of the wheel. Rotation will be along Z-direction

Insert ground to worm revolute joint by selecting the inner face of worm gear. The direction of rotation along the Z-direction

Insert 1.5mm mesh. Adaptive sizing is tuned on and smoothing is kept high

Insert 15 steps in analysis settings. For 1st step, the initial time step is 0.2s, the minimum time step is 0.2s and the maximum time step will be 0.5s. Switch on large deflection and weak springs to be program-controlled with no contact miscellaneous in output controls.

For steps 2-15, initial time step is 0.2s, the minimum time step is 0.2s and the maximum time step will be 0.5s with the carry-over time step switched on.

Insert joint load rotation in the Z direction with magnitude in the form of tabular data.

Force convergence

3. Results, Conclusion and Report presentation

Equivalent stress (Animation: https://drive.google.com/file/d/13x9DVBUd8DDkn_1-pLen1WiEK9vATUwZ/view?usp=sharing )

Equivalent elastic strain (Animation: https://drive.google.com/file/d/1vKRCduU6ju-KhHhjBj-KLFqofAeygZPo/view?usp=sharing )

Total deformation (Animation: https://drive.google.com/file/d/1_lHrpbcnwEppaLj3GxwdjNdYnIGhA4a2/view?usp=sharing )

Equivalent stress	1324.1 MPa
Equivalent elastic strain	0.0067385
Total deformation	7.2512 mm

Maximum equivalent stress of 1324.1 MPa occurs at the base of the worm wheel due to the absence of any fillet feature and also at the line of action where the tooth of worm gear and wheel intersects. There is a slight increase in the elastic strain below the tooth portion. However, the maximum value of total deformation occurs at 7.2512mm. All the teeth of the wheel get deformed. There is no significant change in the deformation for worm gear.

4. Simulation files

Files are attached