Week 1 Spur Gear Challenge
Abstract:
A suitable material among Cast Iron, Cast Steel, Cast Bronze for a spur gear model is selected using Finite element analysis. This selection is based on the criterion of Equivalent Stress (Von Mises), Total deformation, and Stress Intensity.
Introduction:
The most widely used method to solve complex engineering and mathematical problems is the Finite Element Method. It is using this potent method, we determine the most suitable material for the spur gear model created. We use a simple spur gear mechanism depicted in Figure 1.
Figure 1. Model of the Spur Gear
Materials used for the simulation are Cast Iron, Cast Steel, Cast Bronze found in the library of ANSYS directly. Meshing for the model is done with element size 1 mm. The meshing is depicted in Figure 2.
Figure 2. The meshing of the Spur gear model.
Simulation and Results:
The rotation for left spur gear is given at 30 degrees per second and a torque of 10 N-m is given for the right spur gear for this simulation to mimic a real-life spur gear mechanism.
The following are the results of the simulation.
Cast Iron:
- Equivalent Stress
Figure 3. Equivalent Stress for Cast Iron Spur Gear model
- Total Deformation
Figure 4. Total Deformation of Cast Iron Spur Gear model
- Stress Intensity
Figure 5. Stress Intensity of Cast Iron Spur Gear model
Cast Steel:
- Equivalent Stress
Figure 6. Equivalent Stress of Cast Steel Spur Gear model
- Total Deformation
Figure 7. Total Deformation of Cast Steel Spur Gear model
- Stress Intensity
Figure 8. Stress Intensity of Cast Steel Spur Gear model
Cast Bronze:
- Equivalent Stress
Figure 9. Equivalent Stress of Cast Bronze Spur Gear model
- Total Deformation
Figure 10. Total Deformation of Cast Bronze Spur Gear model
- Stress Intensity
Figure 11. Stress Intensity of Cast Bronze Spur Gear model
The animation of the results can be found here:
- Cast Iron - https://drive.google.com/drive/folders/1w_5sT-2YG1ncgBc095tFav6XkFtDgK46?usp=sharing
- Cast Steel - https://drive.google.com/drive/folders/1YskDOAD4wedndifgcj1xbFZqrzZtgAGk?usp=sharing
- Cast Bronze - https://drive.google.com/drive/folders/1e4BOfDuxKGlKcwH59rY5zE49Yxwl7KXZ?usp=sharing
The following table shows the comparison of the results of each material:
Table 1. Results of the simulation of Cast Iron, Cast Steel, Cast Bronze Spur Gear Models
Conclusion:
From the above stress intensity results, the location of possible fracture is at the bottom(or root) of the gear teeth where the stress intensity is maximum. It is in accordance with the theoretical results of high bending moment at the root or the bottom of the teeth and hence the results are justified.
Also, form the ultimate tensile strength values of the materials, Cast Bronze is not suitable for gear mechanism because the maximum stress intensity value is more than its ultimate tensile strength value. But to choose a better material, from the above table Cast Iron seems to be the better option.
Hence, Cast Iron is a better material for the given spur gear mechanism arrangement among all three as it has the least maximum stress intensity among the three materials and also less than its ultimate tensile strength.