This study proposes an analytical methodology to assess the risk to the operation of an offshore wind turbine in order to identify critical assemblies. The gearbox is one of the critical assemblies regarding maintenance costs and downtime. Failure investigation shows that the high speed shaft bearings are one of the gearbox components with a higher probability of fatigue damage. A physics-based model is developed to calculate the accumulated damage and to estimate the remaining useful life. The model is created for a 3 stage gearbox with two planetary and one parallel helical gear.
This paper summarises the methodology and results of a damage accumulation calculation under a load spectrum derived from 1 year of SCADA data. The final results are consistent with the damage levels found in the failure investigation.