风电叶片预埋型叶根连接螺栓抗疲劳优化设计研究

RESEARCH ON FATIGUE STRENGTH OPTIMIZATION OF BUSHING CONNECTION BOLTS FOR WIND POWER BLADES

疲劳断裂是风电叶片叶根连接螺栓的主要失效形式。本文在«典型参数对风电叶片预埋型叶根连接螺栓承载性能的影响»分析数据的基础上,增加分析了变桨轴承高度、螺栓套外径对连接螺栓疲劳性能的影响;采用典型的疲劳载荷,综合分析对比了螺栓预紧力、法兰厚度、螺栓套初始螺纹深度、螺栓光杆直径、变桨轴承高度以及螺栓套外径等参数对叶根连接螺栓疲劳性能的影响。分析结果表明:增加变桨轴承高度、增大螺栓套外径是提高连接螺栓疲劳寿命的最有效方法;从减重降本角度考虑,提高连接螺栓的疲劳寿命,应优先考虑减小光杆直径,同时增大螺栓预紧力,如螺栓疲劳寿命仍无法满足设计要求,应依次考虑增大螺栓套外径,增加法兰厚度,增加变桨轴承高度。

Fatigue fracture is the main failure mode of the root connection bolts of wind power blades.Based on the analysis data of"Influence on Bolts of Wind Turbine Blade Root Bushing Connection by Connection Parameters",the influence of another 2 parameters to the fatigue life of bushing connection bolts is analyzed,i.e.,the thickness of pitch bearing and the outer diameter of bushings.Based on the analysis data,the effects of 6 typical parameters on the fatigue strength of blade root connection bolts are studied and compared.The analysis results show that:(1)increasing the thickness of pitch bearing and increasing the outer diameter of bushings are the most effective methods to improve the fatigue life of the connection bolts.(2)From the perspective of weight reduction,in order to improve the fatigue life of the connection bolt,priority should be given to reducing the shaft diameter and increasing the pretension force the bolts.If it is still not satisfied,increasing the outer diameter of bushings,increasing the flange thickness and increasing the thickness of pitch bearing should be considered successively.