基于泊松随机过程的风力发电机叶片疲劳寿命估算

疲劳寿命决定了正常工况下工程结构服役期限的长度,对其进行准确预测对于零部件疲劳强度设计至关重要。由于机械零部件在工作期间经常会受到随机变幅载荷的作用,载荷间相互作用效应现象十分显著,导致单次循环载荷对材料所造成的疲劳损伤量发生变化,若忽略该效应会影响疲劳寿命估算的准确性。针对当前研究中的疲劳损伤累积法则无法考虑该效应的问题,提出一种将非齐次泊松随机过程函数与伴随损伤理论相结合来估算零部件疲劳寿命的方法,解决了由于载荷间相互作用效应所带来的载荷作用顺序的问题,并以随机加载试验为例验证了该方法的准确性。将其应用于风力发电机叶片的疲劳寿命估算过程中,结果表明该方法可靠、有效,为风力机叶片的疲劳可靠性设计提供了新的路径。

Estimation of Blade Fatigue Life of Wind Turbine Based on Poisson Stochastic Process

Fatigue life determines the length of the service life of engineering structure under normal working conditions, and it is very important to predict the fatigue life accurately for the fatigue design of parts. Due to mechanical parts subjecting to random variable load during the working time, the interaction effect between loads is significant which changes the fatigue damage caused by single cycle load. Ignoring this effect will affect the accuracy of the estimation of fatigue life. In the current study, the fatigue damage accumulation rule cannot be considered. To solve this problem, a method for estimating the fatigue life of components by combining the non-homogeneous Poisson stochastic process function with the theory of the concomitant damage is put forward, which takes the problem of loading sequence caused by the interaction effect between loads into account. The accuracy of this method is verified by the random loading test. It is applied to the estimation of the fatigue life of wind turbine blades. The results show that this method is reliable and effective, which provides a new path for the fatigue reliability design of wind turbine blades.