Rolling Contact Fatigue Life Formula |
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\( L \;=\; \left( \dfrac{ C }{ P } \right)^p \) (Rolling Contact Fatigue Life) \( C \;=\; P \cdot L^{1/p} \) \( P \;=\; \dfrac{ C }{ L^{1/p} } \) |
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| Symbol | English | Metric |
| \( L \) = Rolling Contact Fatigue Life | Millions of Revolutions / Hr \(dimensionless\) | Millions of Revolutions / Hr \(dimensionless\) |
| \( C \) = Basic Dynamic Load Rating of the Rolling Element (Force) | \(lbf\) | \(N\) |
| \( P \) = Dynamic Applied Load (Force) | \(lbf\) | \(N\) |
| \( p \) = Life Component (3 for Ball Bearings) (10/3 for Rolling Bearings) | \(dimensionless\) | \(dimensionless\) |
Rolling contact fatigue life, abbreviated as \( L \), is the expected number of load cycles or operating time that a component subjected to rolling contact, such as bearings, gears, or cam–follower systems can endure before fatigue failure occurs. This type of fatigue arises from repeated Hertzian contact stresses generated where curved surfaces roll against each other under load. Although the contact may appear smooth, subsurface shear stresses develop beneath the contact area, leading to the initiation and growth of microscopic cracks. Over time, these cracks propagate to the surface, resulting in material flaking or spalling. Rolling contact fatigue life is influenced by factors such as load magnitude, contact geometry, material properties, surface hardness, lubrication quality, residual stresses, and operating conditions. Engineers use rolling contact fatigue life to predict durability, establish maintenance intervals, and design components that can reliably withstand repeated rolling stresses throughout their intended service life.
