随机地震动摇摆分量对风电塔结构地震响应影响的分析

Seismic analysis of wind turbine towers under rocking earthquake components

我国目前为世界第一风电装机大国,合理的抗震设计是确保风力发电塔架安全性的重要措施。常规的结构地震响应分析多考虑水平地震作用,鉴于风电塔结构高耸的特点,有必要对地震动摇摆分量对风塔地震响应的贡献进行分析。基于风电塔结构单自由度简化体系,发展了在地震动摇摆分量下结构响应的随机振动分析方法。利用这种方法,对额定功率为1.25MW和5MW的风电塔进行数值分析。结果表明,这两座风电塔地震动在摇摆分量作用下塔顶位移极值期望与地震动水平分量作用下塔顶位移极值期望的比值分别为1.80%和1.93%,可以认为地震动摇摆分量对65m和90m这两个高度的塔顶位移贡较小。但对于更高的风电塔,仍在做进一步的统计计算。

The total wind turbine capacity of China is the largest in the world. Reasonable seismic design is one of key strategies to ensure wind turbine tower safety. Typical seismic analyses mainly consider horizontal ground motions. Due to the tall and slender feature of wind turbine towers,it is essential to perform structural analyses of wind turbine towers under earthquake rocking components. A simplified stochastic seismic analysis method was developed based on the SDOF assumption in this paper. Two wind turbine towers with 1. 25 MW and 5 MW turbines,respectively,were analyzed by using this method. It is found that the ratio between the extreme value expectation for the tower tip displacement under rocking earthquake component and that under translational components for these 65m and 90m tall towers are 1. 80% and1. 93%,respectively,which indicates that there is insignificant seismic displacement responses contributed by the rocking earthquakes for these two studied wind turbine towers. Further research is on-going to provide conclusive suggestion for taller wind turbine tower design under earthquake rocking components.