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Plain Bearing Failure
5.0 Fretting
| Click on photograph to enlarge | |
 | Fretting damage to journal bearing subject to vibration when stationary |
| Main Characteristics | Fretting when the machine is stationary occurs in line with the gravity load; in the Photograph this is in the centre of the bearing, not displaced to one side as it would be if the damage had occurred at the point of minimum oil film thickness during running. |
| Cause | This is caused by external vibration that causes small oscillatory movement at the point of contact between journal and bearing. |
| Note | |
| Possible Confusion with Other Types of Damage | |
| Comment | The damage resembles a start-up witness mark or wipe (see Section 1.1: Start-up wiping damage), but is much more severe. |