e-POSTER: Vibration-Induced Bolt Self-Loosening Phenomenon in Critical Wind Turbine Applications
21 May 19
1:00 PM
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1:25 PM
Tracks:
Operations and Maintenance, Poster Presentations
It is vital that bolted joints holding sub-assemblies together remain secure. Fasteners used to secure bolted joints should resist the loosening caused by vibrations and dynamic loads, while keeping the ease of removal during maintenance. When a threaded fastener is subjected to vibration, the rapid transverse movement causes a lowering of friction against the contact planes and unintentional bolt self-loosening occurs. The self-loosening phenomenon causes the fasteners to vibrate loose and could lead to catastrophic consequences for critical wind applications. To mitigate the problem of unintentional bolt self-loosening, one must understand what parameters are critical in the bolted joint that influences this. The critical displacement threshold and the Junker vibration principle will be discussed to understand the bolt self-loosening phenomenon and preventative measures. There are many locking methods out on the market today to prevent this bolt self-loosening phenomenon from occurring. While some are effective when the dynamic loads are mild, certain applications within wind turbines, such as blade bolts, need to have a locking method that can withstand harsh dynamic and vibratory conditions. The Junker vibration test will analyze these locking systems to compare among them how effective they are under extreme transverse loading conditions where bolt self-loosening is most susceptible. Several locking methods will be compared under this test procedure and analyzed.