Week 1 Spur Gear Challenge
STRUCTURAL ANALYSIS OF SPUR GEAR
OBJECTIVE
- Conduct static structural analysis for spur gear with three different materials and compare Equivalent Stress, Total Deformation, Stress Intensity and Location for possible Fracture.
- Write a detailed report comparing the result and suggest the suitable material.
CASE SETUP AND EXECUTION
STRESS INTENSITY
The stress intensity factor is a concept in Fracture Mechanics that is used to measure the stress concentration at a crack tip. In safety design, It is compared to a critical value and evaluate whether a component or structure is prone to fracture. The critical value is typically a material parameter, and varies from material to material.
CONTACTS:
- 26 faces of each gear are selected as frictional contact having zero coefficient of friction.
JOINTS
- Left gear has given revolute joint with free rotation and right gear is provided with a constant torque of 10N-m in 6 equal steps.
MESHING
- Element size-1.0mm
- Nodes-16474
- Elements-2808
CASE-1(CAST IRON)
EQUIVALENT STRESS
TOTAL DEFORMATION
STRESS INTENSITY
CASE-2(CAST STEEL)
EQUIVALENT STRESS
TOTAL DEFORMATION
STRESS INTENSITY
CASE-3(CAST BRONZE)
EQUIVALENT STRESS
TOTAL DEFORMATION
STRESS INTENSITY
REPORT AND ANALYSIS
| MATERIAL | YEILD STRENGTH | EQUIVALENT STRESS | TOTAL DEFORMATION | STRESS INTENSITY |
| CAST IRON | 79.81 Mpa | 364Mpa | 30mm | 386 Mpa |
| CAST STEEL | 349 Mpa | 387Mpa | 30mm | 413Mpa |
| CAST BRONZE | 144 Mpa | 361Mpa | 30mm | 387Mpa |
- In all the three cases the equivalent stress exceeded the yeild strength,so the geometry of the gear need to increase to accomadate the load.
- The possible place for failure is at the maximum stress point.
- Since the fatigue strength has not given the fracture cant be calculated.
- Among these three materials cast steel have high yeild strength so it can be selected.