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中文核心期刊

风荷载作用下风机结构振动稳定性研究

Vibration stability of wind turbine structure under wind loads

  • 摘要: 风机结构因其高耸细长、承受大质量等特点,在风荷载作用下容易发生动力失稳。由于风机结构失稳的影响因素较多,目前的研究考虑了部分风机塔筒结构变量与风机稳定性的关系,但缺少对风机结构在极端风荷载作用下多种参数综合影响的研究;且现有的理论大多从静态和实证角度出发对结构的稳定和安全评价进行分析,而针对结构突变失稳的机理分析结果较少。为探究极端风荷载作用下风机结构的失稳特性,本文将风机结构简化为悬臂梁模型,利用总势能不变值原理建立了考虑风机结构大变形的非线性振动方程,将作用于风机结构上的脉动风简化为简谐荷载,基于尖点突变理论得到了风机结构稳定振动的判别方法,作为风机结构发生动力失稳的判别条件。研究结果表明:当风机塔筒参数不满足稳定振动条件时,结构振幅随外荷载频率增加会出现跳跃现象,造成位移的突变,从而导致风机结构产生突变失稳;当满足稳定振动条件时,通过增大阻尼系数、增大塔筒外径、减小风机高度可以提高最大风速,保证风机结构稳定性。计算结果表明,本文得到的理论分析结果与数值模拟结果较为接近,验证了本文提出的风机结构稳定振动判别方法的有效性和可靠性,该方法可为风机结构的抗极端风设计及失稳分析提供一定的理论参考和工程指导。

     

    Abstract: The wind turbine structure is tall and bears large mass at the top. Dynamic instability is easy occurred in wind turbine structure under wind load. Due to many influencing factors of the instability of wind turbine structure, the relationship between part of variables and the stability of wind turbine structure is considered in current research. The relationship between certain structural variables of wind turbine towers and the stability of wind turbines has been considered in current research, but it lacks research on the comprehensive impact of multiple parameters on the structure of wind turbines under extreme wind loads. The most existing theories analyze the stability and safety evaluation of structures from a static and empirical perspective, with fewer results focusing on the mechanism analysis of structural catastrophic destabilization. A nonlinear vibration equation that accounts for the large deformation of the wind turbine structure is formulated based on the principle of the conservation of total potential energy. A method for assessing the stable vibration of wind turbine structures is developed based on cusp catastrophe theory. When the wind turbine tower fails to satisfy the conditions for stable vibration, the catastrophe displacement of the structure will happen as the frequency of external loads increases. The wind turbine structure will be catastrophic destabilization. When the stable vibration conditions are satisfied, the maximum wind speed can be increased by increasing damping coefficient and outside diameter of the tower. The maximum wind speed can also be increased by reducing the height of the wind turbine structure. The theoretical analysis results show close agreement with numerical simulation results. This method can provide valuable theoretical references and engineering guidance for designing wind turbine structures under extreme wind loads.

     

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