大兆瓦风机主轴法兰螺栓疲劳寿命评估方法研究

Fatigue Life Assessment Method for Large Megawatt Wind Turbine Spindle Flange Bolts

大兆瓦风电机组主轴法兰螺栓连接受到复杂交变载荷的作用,极易产生疲劳破坏。针对此问题,构建法兰螺栓连接有限元数值模型,以法兰界面涂层增摩工艺为背景,分析不同预紧力工况下法兰连接各部件危险部位应力变化规律。通过GH-Bladed结合雨流计数法给出螺栓实际载荷数据,根据Eurcode3规范修正材料S-N曲线,使用FE-SAFE得到了不同预紧力下螺栓连接疲劳寿命,明确了法兰界面涂层增摩、预紧力变化对螺栓连接疲劳寿命的影响,提出了基于法兰结构的螺栓疲劳寿命评估方法。结果表明:增大法兰界面的摩擦因数,在850~1100 kN内降低螺栓预紧力有益于改善螺栓连接的疲劳寿命。

Large megawatt wind turbine spindle flange bolted connections are subject to complex alternating loads,which is highly susceptible to fatigue damage.A finite element numerical model of bolt connection was constructed,taking the flange interface coating friction enhancement process as the background,the stress change law of the dangerous parts of flange connection was analyzed under different preload conditions,the actual load data of bolts were given by GH-Bladed and combined with rain flow counting method,the material S-N curves were modified according to Eurcode3 specification.The fatigue life of bolt connection under different preloads was obtained by using FE-SAFE,and the influence of the flange interface coating friction increase and preload change on the fatigue life of bolt connection was clarified,and the fatigue life evaluation method of bolt based on flange structure was proposed.The results show that increasing the friction coefficient of the flange interface and reducing the bolt preload 850~1100 kN a certain within range are beneficial to improve the fatigue life of the bolted connection.