Engineers from the University of Sheffield in South Yorkshire, England, have developed a novel technique to predict when bearings inside wind turbines will fail, which could make wind energy cheaper. The method, published in the journal Proceedings of the Royal Society and developed by Mechanical Engineering research student Wenqu Chen, 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, Wind Daily reported.
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 uses a customized piezoelectric sensor mounted in the bearing to measure the time of flight and determine the load.
This sensor is less expensive and significantly smaller than currently available, making it suitable for smaller turbines. It can also provide a better prediction of the maintenance needed, saving money in servicing.
