基于周期对称模型的MW级风电机组变桨轴承连接螺栓强度计算

针对MW级风机变桨轴承连接螺栓的强度分析问题,采用周期性建模的方式建立了螺栓的有限元分析模型,并基于GL规范计算了螺栓的极限强度及疲劳强度。首先在最大预紧力工况下基于最大极限载荷计算得到了螺栓的最小极限安全系数。然后通过比较3个叶片的极限疲劳载荷得到了最大的极限疲劳载荷,在最小预紧力工况下基于该载荷得到了螺栓的载荷-应力非线性曲线,构建了新的载荷谱并根据载荷-应力曲线将该载荷谱转化为应力谱,利用雨流统计和Palmgren-Miner准则得到了螺栓的最小疲劳安全系数。计算结果表明,变桨轴承与轮毂连接螺栓和变桨轴承与叶片连接螺栓的极限、疲劳强度满足设计要求;该方法减少了有限元的计算量,为螺栓的强度分析提供了新的思路。

Strength assessment of pitch bearing bolt connection of MW wind turbine based on periodic symmetric model

Aiming at the problems of strength assessment on the pitch bearing bolt connection of MW level wind turbine,the ultimate strength and fatigue strength were calculated based on the periodic symmetric model and GL guideline.The minimum ultimate safety factors were calculated by using the maximum extreme loads for the maximum bolt pretension level.Then,the maximum ultimate fatigue loads were calculated by comparing with the ultimate fatigue loads of three blades and the bolt load-stress nonlinear curves were obtained for the minimum bolt pretension level.A new load spectrum was constructed and was transformed to stress spectrum according to the interpolation of bolt loadstress nonlinear curves.The minimum fatigue safety factor were calculated by the rainflow method and Palmgren-Miner criterion.The results show that the ultimate and fatigue strength safety factor meet the design requirements.The method reduces the calculation amount and provides a new approach for the strength assessment of bolt.