倾覆力耦合的大兆瓦风机主轴-齿轮箱法兰结构疲劳寿命研究

Study on fatigue life of large-megawatt wind turbine’s spindle-gearbox flange structure coupled by overturning force

大兆瓦风机主轴-齿轮箱法兰连接受倾覆力及其他交变载荷的作用,极易产生疲劳破坏。文中建立了考虑倾覆力耦合作用的法兰连接有限元数值模型,分析了特定工况下法兰连接各部件应力场分布规律;通过GH-Bladed获得主轴实际转矩变化数据,根据雨流计数法计算得到了主轴和螺栓多种工况下载荷-时间历程曲线,基于Brown-Miller准则并结合材料的S-N曲线,使用FE-SAFE给出了不同预紧力条件下主轴和螺栓的疲劳寿命,疲劳分析结果表明:随着预紧力的减小,主轴的疲劳寿命大于螺栓的,螺栓在风机运行过程中更容易发生疲劳破坏。基于VDI2230规范,结合法兰界面涂层增摩工艺,得到了法兰界面摩擦因数、螺栓预紧力与法兰结构疲劳寿命的理论模型。该研究对于大兆瓦风机主轴-齿轮箱法兰连接结构设计和疲劳寿命提升具有一定的指导意义。

The large-megawatt wind turbine’s spindle-gearbox flange connection is susceptible to fatigue damage due to the influence of the overturning force and other alternating loads.In this article,efforts are made to set up the finite-element numerical model of the flange connection,with the coupled overturning force taken into consideration;then,the analysis is conducted on the stress field distribution of the flange connection’s each component under specific working conditions.The data on the spindle’s ever-changing torque is obtained with the help of GH-Bladed;the load-time history curves of the main spindle and the bolt under various working conditions are calculated according to the rain flow counting method;based on the Brown-Miller criterion and in combination with the material S-N curve,FE-SAFE is used to work out the fatigue life of the spindle and the bolt with different preloads.The results show that the fatigue life of the spindle is greater than that of the bolt as the preload decreases;the bolt is more prone to fatigue damage when the wind turbine is in operation.According to the VDI2230 specifications,combined with the coating friction-enhancement process applied on the flange interface,the theoretical model is set up for the flange interface’s friction coefficient,the preload force exerted on the bolt and the flange structure’s fatigue life.This study provides guidance to develop the large-megawatt wind turbine’s spindle-gearbox flange structure and extend its fatigue life.