中文摘要：

针对风浪联合作用下海上风机支撑结构的疲劳问题,提出一种频域疲劳评估方法.基于风浪散布图,提出风浪联合作用下疲劳热点应力功率谱密度函数的组合方法,并提出多载荷联合作用下最大主应力线性化方法.利用多输入线性系统理论,得到风载荷作用下热点应力功率谱密度函数的计算方法,并对各种谱疲劳损伤计算方法进行对比分析.以3 MW导管架式海上风机支撑结构为研究对象,验证所提方法的计算精度,风载荷作用下热点应力功率谱密度函数计算结果与时域模拟结果吻合较好.该方法简便有效,可用于风机支撑结构疲劳的快速评估.

英文摘要：

A frequency-domain fatigue assessment method was proposed in view of the fatigue problem of support structure in offshore wind turbine under combination of wind and wave loads.The combination method power spectrum density function of hot spot stress under combination of wind and wave loads was presented on the basis of wind-wave scatter diagram.A linearization method for the first principal stress under multi-loads was developed.The power spectrum density function calculation method of hot spot stress under wind load was obtained by using the multi-input linear system theory.Different spectral methods for predicting the fatigue damage were compared.Finally,the accuracy of the proposed method was verified by taking a 3 MW Jacket type support structure as an example.The power spectrum density functions of hot spot stress under wind load are in good agreement with the time domain simulations results.The proposed method is convenient and effective,which can be used for the fast fatigue assessment of support structure.