报告题目：Effects of Extreme Loading Conditions on Premature Failures of Large Scale Wind Turbine Gearbox Bearings
报告人：Dr. Hui Long
报告时间：2015年10月23日 10：00
报告地点：流体力学楼619
报告人简介：
Dr Long joined the University of Sheffield as a Reader in 2012. She was a senior lecturer at Durham University where she worked from 2003 to 2012. Dr Long received her BEng, MSc and PhD degrees in Mechanical Engineering from Chongqing University in China. she worked as a research associate and research fellow at the University of Strathclyde, the University of Wales Swansea and Brunel University, funded by EU and EPSRC research projects. Dr Long’s current research is centred on two broad areas, wind energy and advanced metal forming technology. In wind energy area, the work has been focused on investigation of wind turbine gearbox reliability, stochastic loading and its statistical characteristics due to wind speed variation and wind turbine controls, transient and impact loading caused by operational conditions, and their effects on premature failures of key mechanical components, such as bearing raceway white etching cracks and gear tooth surface micro-pitting. In manufacturing area, the work has been focused on the development of advanced metal forming processes including novel spinning and incremental sheet forming. Both experimental and numerical modelling investigation has been performed to prevent material failures and to improve process formability by optimizing the process design and to achieve a better surface finishing and geometrical accuracy.
报告摘要：
Wind turbine gearbox is one of the subsystems that lead to the most downtime of wind turbines in operation due to their high failure rates. Extreme loading conditions caused by a number of possible sources, which expose gears and bearings in the gearbox to higher than designed contact pressures and surface traction in wind turbine operation, are thought to be one of the important contributors to their failures. The presentation will firstly outline the rapid development of European and UK wind energy market and wind turbine gearbox reliability issues faced by the industry. It will introduce a premature failure mode of bearings, termed as white etching cracking, frequently seen in the large scale wind turbine gearbox. The load measurement data from a large scale wind turbine in operation is presented and the extreme loading conditions are identified. A multi body dynamic model of a wind turbine gearbox and Finite Element modelling of bearing contact surfaces are developed in order to determine bearing contact stress distributions and stress concentrations at subsurface Manganese Sulphide (MnS) inclusions during transient operating conditions. Finally the failure mechanisms of wind turbine bearings caused by white etching crack, a subsurface initiated damage, are discussed. The presentation will conclude with an outline of challenges to develop future more reliable wind turbines for offshore applications.
