该文对风力机叶片损伤导致风轮模态局部化的动力学机理与影响因素进行研究。首先从代数特征值角度,揭示模态局部化的动力学机理,发现结构产生模态局部化的主要原因是存在密集模态。其次,建立NREL 5 MW风轮结构的有限元模型,分析叶片失谐度、模态阶数和失谐位置对风力机风轮结构模态局部化的影响。结果表明：叶片损伤失谐会造成叶片的振型发生显著变化,产生模态局部化现象;同时在某些模态下,系统振动能量集中于损伤叶片,会加速叶片损伤,致使其产生疲劳破坏。因此在风力机结构设计时,需考虑模态局部化对风力机结构的动力学特性影响。
Abstract
This paper investigates the dynamical mechanism and influencing factors of mode localization in wind rotor due to the blade damage. Firstly, the dynamical mechanism of mode localization is revealed from the perspective of eigenvalue, and it is found that the essential cause of modal localization is the existence of closely spaced modes in structures. Then, the finite element model of NREL 5 MW wind turbine rotor is established, and the effects of blade mistuning, modal order, and mistuning position on the model localization of the wind turbine rotor are analyzed. Numerical simulation results indicate that damage mistuning of a single blade can cause significant variations in vibration modes of the wind turbine rotor, triggering mode localization. And the significance of the investigation is that the mode localization will aggravate the blade damage and potentially cause fatigue damage of the blade in some modes. Therefore, it is necessary to consider the effect of mode localization on the dynamic characteristics of wind turbines during wind turbine design.
关键词
风力机 /
风轮 /
模态局部化 /
密集模态 /
失谐 /
有限元法
Key words
wind turbines /
wind rotor /
mode localization /
close modes /
mistuning /
finite element method
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基金
国家自然科学基金（51778103）; 广东省自然科学基金（2021A1515011770）; 汕头大学科研启动基金（NTF18012）
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