Thanks for the responses.
The failure is due to fatigue, resulting from the combined stress.
The component that failed is a stub shaft at the drive end of a horizontal rotor. One end of the shaft is bolted to the main section of the rotor, the other end supports a shaft mounted gearbox and...
Due to a design error a shaft supporting a horizontal rotor has failed. The manufacturer has agreed that the failure is due to a design fault and is replacing the shaft. The manufacturer has provided design calculations, which appear to be ok, but I need to check the various factors and...