Engineers from the University of Sheffield have developed a novel technique to predict when bearings inside wind turbines will fail, which could make wind energy cheaper. The method uses ultrasonic waves to measure the load transmitted through a ball bearing in a wind turbine. The stress on wind turbine is recorded and then engineers can forecast its remaining service life.
When a bearing is subject to a load, its thickness is reduced by a very small amount due to elastic deformation, and the speed of sound is affected by the stress level in the material. Both these effects change the time of flight of an ultrasound wave through a bearing. The new method is the only way to directly measure the transmitted load through the rolling bearing components. It can also provide a better prediction of the maintenance needed, saving money in servicing.