风力机叶片在拍打方向的载荷估计与可靠性分析

Load Estimation and Reliability Analysis of Wind Turbine's Blade in Flap-wise

为了保证风力机在复杂的载荷下安全、稳定运行,提出了一种用于分析风力机叶片在拍打方向上的疲劳概率模型．该模型利用应力-强度干涉理论,并且假定风速服从威布尔分布．考虑风速的不稳定性作用,在风力机叶片上分布载荷的不确定因素,并假定风力机的设计寿命为20a．在拍打方向上的疲劳概率通过一阶可靠性方法计算．计算了风速为12m／s,湍流度为I=0．02、0．1、0．15、0．2的4种情况,并对耿贝尔分布、三参数威布尔分布以及威布尔分布3种分布进行了比较．通过比较得知,耿贝尔分布的直线性比较好,而三参数威布尔分布以及威布尔分布都有尾部现象．最后,以600kw风力机叶片为例,通过应力-强度干涉理论来对叶片的可靠性进行估算．计算结果表明该台风力机符合可靠性要求．

In order to ensure wind turbine running safely and steadily in complicated environment, a probabilistic model for analysis of the failure of a wind-turbine rotor blade in flap-wise bending is presented. This model capitalizes on stress-strength interference theory and curve, and Weibull model about the wind＇s distribution is considered. This model accounts for the uncertainties about the loads acting on the wind-turbine rotor blade by the unstable wind distribution. A 20-year design lifetime is assumed. The probability of fatigue failure in flap-wise bending of the rotor blade is calculated by means of a first-order reliability method. Four situations are calculated when turbulence intensities are 0.02, 0.1, 0.15, 0.2 and wind velocity is 12 m/s. Conclusions can be draun through comparison： linearity of Gumbel distribution is better than one of three-parameter Weibull distribution and Weibull distribution, because the two distributions have some tails. At last, Stress-strength Interference Theory model is validated by 600 kW wind turbine blade. Conclusion has chown that wind turbine rotor blade can meet the design standards.