Wind Turbine Bolt Inspection Utilising Ultrasonic Phased Arrays

Bolts are vital for the long and safe running of wind turbines both on and offshore, they can be found in in multiple areas within the Nacelle as well as ancillary structures. Here we carry out ultrasonic phased array inspection of two main types of bolts in a turbine with induced defects and show the results.

In-service bolts can fail for multiple reasons, the primary failure mechanism we aim to detect in these bolts are cracking defects located anywhere in the bolt, these are most likely to appear at high stress points e.g. contact points with the threaded bolt or the item being joined. 

Traditionally bolts are either replaced after a set time period regardless of their condition, or removed and visually inspected for their integrity, this is both expensive and time consuming and generally requires the turbine to be shut down or run at reduced capacity.

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