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PLAIN BEARING FAILURE
4.0 Cavitation erosion
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4.1 Discharge Cavitation Erosion Damage in Reciprocating Engine Bearings
4.2 Suction Cavitation Erosion Damage to Reciprocating Engine Bearings
4.3 Cavitation Erosion of White Metal Thrust Collar
4.4 Cavitation Damage Caused by Bearing Instability
4.5 Cavitation Damage - Summary
This is a particular form of fatigue caused by rapid fluctuation of pressure in the bearing oil film. When the pressure is low, bubbles of vapour or dissolved gas are formed and then collapse as they go into a high pressure region.
Vaporous cavitation, where the bubble collapse is much more violent, results in shock waves in the lubricant film that cause fatigue failure in the white metal surface. This differs from normal fatigue in that small pits are formed rather than loose pieces.
Cavitation damage occurs where there are reciprocating loads, either as part of the normal loading cycle or because of high-frequency vibration. It can also occur in bearings where there are sharp discontinuities in the thickness of the bearing oil film
Gaseous cavitation, in which the bubbles are of gas from solution in the lubricant, is much less energetic than vaporous cavitation as bubble dispersion depends on re-absorption of the gas by diffusion rather than instantaneous collapse. Gaseous cavitation can still, however, cause damage to soft white metal bearings.