Page 326 - Analysis and Design of Machine Elements
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Analysis and Design of Machine Elements
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(a)
(b)
Figure 11.10 Stress variation in bearing components.
11.2.4 Potential Failure Modes
Since the inner ring, outer ring and rolling elements experience variable stresses during
bearing operation, surface fatigue failure is a predominant failure mode in bearings. As
discussed before, the cyclic subsurface Hertzian contact stresses, combined with manu-
facturing defects, may initiate minute cracks. These minute cracks may propagate during
cyclic loading and ultimately cause surface pitting. Failure is considered to occur when
either raceway or rolling elements exhibit first pit. Typically, the raceways pit first, result-
ing in noise, vibration and heat.
