风荷载的非高斯性对风机结构疲劳损伤的影响

Influence of non-Gaussian characteristics of wind load on fatigue damage of wind turbine

为分析非高斯风荷载作用下风机结构的疲劳寿命,在穿越模型基础上,根据Monte Carlo模拟生成某典型风机正常风速条件下,高斯、非高斯硬化和软化3种风场的风速时程,用于分析风场的非高斯性对风机结构疲劳损伤的影响.由叶片的气动模型和多体动力,计算出风机的动力响应,并对响应的时域特性进行分析.基于线性损伤累积和线性裂纹扩展理论,对裂纹形成寿命和裂纹扩展寿命进行详细讨论.结果表明:不同概率特性风场作用下风机动力响应的最大值有所不同,且风机响应的非高斯性较风场的非高斯性减弱;在年平均风速较小地区,风场的非高斯性对风机疲劳寿命影响较小;但随着年平均风速的增大,非高斯性对疲劳寿命的影响显著增大,当年平均风速为7 m/s和9 m/s时,相较于高斯风场,软化过程的裂纹形成寿命减小约10%.因此,在年平均风速较大地区,需要考虑风场的软化特性对风机结构疲劳损伤的影响.

Based on translation models, both Gaussian and non-Gaussian wind fields were generated using Monte Carlo simulation for investigating the influence of non-Gaussian characteristics of wind load on fatigue damage of wind turbine. With the blade aerodynamic model and multi-body dynamics, dynamic responses were calculated, and probability characteristics of the response were analyzed. Using linear damage accumulation theory and linear crack propagation theory, crack initiation life and crack propagation life were discussed in detail. The results show that the maximum responses under three types of wind fields are different, and non-Gaussian characteristics of wind load are more significant than those of the response. For areas with smaller annual mean wind speeds, non-Gaussian characteristics of wind load have less influence on fatigue life of wind turbine, but the influence becomes significant with the increase of the annual mean wind speed. When the annual mean wind speeds are 7 m/s and 9 m/s, the crack initiation lives under softening non-Gaussian wind decrease by 10% compared with Gaussian wind fields. It concludes that the influence of softening non-Gaussian characteristics should be considered for areas with higher annual mean wind speeds.