Definition - What does Surface Fatigue mean?
Surface fatigue is a failure that occurs due to cyclic loading. Surface fatigue is different from other types of fatigue failures because it is found solely on the top layer of a material. Surface fatigue usually appears in the form of microcracks on a material's surface. If left unchecked, the failure could spread past the surface of the material.
Corrosionpedia explains Surface Fatigue
Surface fatigue can have several different causes, including:
- Repeated impact
- Repeated shear stresses
- Fretting wear, or wear that is caused by a oscillating contact between two members
Surface fatigue is a common problem with gears. When gears with rough edges and insufficient lubrication come together repeatedly, they produce a cyclical stress. This cyclical stress can create discontinuities on the surfaces of the gear. As repeated stress is continuously applied to the gear, the discontinuities may turn into microcracks or micro pits on the surface of the gear. This can ultimately lead to a complete failure of the gear.