Week 1 Spur Gear Challenge

Aim: Compare and conclude for the design choice on the best-suited material for spur gear design.

Pre-Processing:

The geometry is loaded into the Ansys workbench. Then the material properties are added to the library and chosen for different cases as follows:

case 1. Cast Iron,

case 2. Cast Steel,

case 3. Cast Bronze.

Mesh:

Case 1The mesh size of 1mm was given.

Case 2 The mesh size of 1mm was given.

Case 1The mesh size of 0.8mm was given.

Connections:

In all the cases the connections were defined by frictional contact with 0.3 friction coefficient. The joints were specified as revolute for two gears with the ground as a reference.

Analysis Settings:

The analysis was set for 6 steps with an initial step time of 0.2 seconds, a minimum time step of 5e-002, and a maximum time step of 0.5seconds.

The right joint was rotated 180 degrees and the left joint was given a moment of 10N-m.

Post Processing:

The equivalent stress, total deformation, and max principal stress results were requested.

Results:

The results are tabulated below and the corresponding simulation images are attached.

	Cast Iron	Cast Steel	Cast Bronze
Equivalent Stress (Pa)(von-mises)	3.5658e8	3.5819e8	4.0128e8
Deformation(m)	0.03	0.03	0.03
Max (Pa) Principal Stress	3.6781e8	3.7068e8	4.1397e8

Image: Cast Iron Equivalent Stress

Image: Cast Iron Deformation

Image: Cast Iron Max Principal Stress

Image: Cast Steel Equivalent Stress

Image: Cast Steel Deformation

Image: Cast Steel Max Principal Stress

Image: Cast Bronze Equivalent Stress

Image: Cast Bronze Deformation

Image: Cast Bronze Max Principal Stress

Conclusions:

• The results show that the maximum principal stress occurs at the tooth intersections. This is a place where a possible fracture can take place.
• Stress intensity factor is the magnitude of the stress field around the crack tip. Since there is no fracture occurring or crack growth in the model the stress intensity factor cannot be added using the fracture tool during post-processing.
• It can be deduced that the cast bronze cannot be used as high stresses are being developed.
• The choice of material between cast iron and cast steel is a bit difficult as the results closely differ. But the edge is for cast iron in terms of property and also the cost of cast iron is lower to cost of cast steel which is the reason why cast iron is my choice of material for this application.