给出了海上风电机组基础波浪荷载导致的疲劳损伤计算方法。基于随机波浪理论,依据海浪谱将随机波浪转换为一系列线性波的组合,由Morison方程计算得到波浪荷载并进行线性化。根据线性波浪荷载作用下结构的动力分析,求得结构响应并计算得到频域范围内的结构应力传递函数。根据海浪谱和应力传递函数,进而得到结构的热点应力谱。由某海域的海况分布,依据Miner线性累计损伤准则,通过假定结构长期热点应力分布为短期Rayleigh分布的组合,计算得到结构在设计周期内的累计疲劳损伤。以某单桩基础为例,验证了计算方法的可行性。计算方法对海上风电机组基础的浪致疲劳设计具有参考价值。
This paper presents an approach to calculate the fatigue damage of offshore wind turbine foundation caused by wave load. On the basis of wave spectrum and random wave theory, random sea wave was transformed into a series of linear waves. The wave force was obtained and linearized by employing the Morison equation. Through dynamic analysis on the foundation structure under the liner wave force, the structure response was obtained to calculate the transfer function of structural stress within the frequency area. Furthermore, the stress spectrum of hot spot was obtained based on the wave spectrum and transfer function. By assuming that the long period hot spot stress distribution obeys short time Rayleigh model, the accumulated fatigue damage of the structure in a sea area in designed lifetime was obtained in the light of the Miner’s theory. A single-pile foundation case is taken to verify the feasibility of this calculation approach. This research could be a reference for the fatigue design of offshore wind turbine foundation.
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