弯扭耦合作用下变频风机叶片断裂分析与治理技术研究

针对某变频运行风机发生的叶片断裂故障，采用无线应变测试技术获取了不同工况下转轴扭矩脉动特性。建立叶轮叶片有限元模型，获取风机各阶模态特性；将实测脉动扭矩作为激励，计算扭矩脉动下叶片所承受的应力特性。结果表明：电机输出谐波可能激发叶片轮盘弯扭耦合共振，导致叶片局部应力增大，进而疲劳断裂；叶片顶部加之字形加强筋可以有效减小叶片振动，预防断裂。

Study on fracture analysis and treatment technology of variable frequency wind turbine blades under the action of bending and torsion coupling

To solve the blade fracture fault of a variable frequency wind turbine in operation, the torque pulsation characteristics of the rotating shaft under different working conditions were obtained by using the wireless strain test technology. A finite element model of the impeller blade was established to obtain the modal characteristics of the wind turbine at each order; using the measured pulsating torque as the excitation, the stress characteristics of the blade under the torque pulsation were calculated. The results show that the harmonic output of the motor may stimulate the bending and torsion coupling resonance of the blade disk, which leads to the increase of the local stress of the blade, and then the fatigue fracture; the zigzag reinforcement on the top of the blade can effectively reduce the blade vibration and prevent fracture.