基于模态力谱的不同风谱风振效应差异分析  

Comparison between wind-induced vibrations of different spectrums based on modal force spectrum

作　　者：张军锋[1] 刘庆帅 Zhang Junfeng;Liu Qingshuai(School of Civil Engineering,Zhengzhou University,450001,Zhengzhou,China)

机构地区：[1]郑州大学土木工程学院,郑州450001

出　　处：《应用力学学报》2020年第2期730-736,I0019,共8页Chinese Journal of Applied Mechanics

基　　金：国家自然科学基金(51508523)。

摘　　要：为明确风谱对顺风向风振效应的影响,选择工程常用的Davenport谱与Simiu谱,基于随机振动理论,对一座典型独柱式避雷针的风振效应进行了多种工况的频域计算,并提出采用模态力谱而非直接使用风谱判断风振响应的大小。研究表明:Davenport谱不随高度变化,而Simiu谱随高度变化,难以通过风谱的对比直接确定各自所得风振响应的大小,但模态力谱可综合考虑整个结构表面脉动风场的贡献,对于以单一模态为主的响应,可准确评价不同风谱所得风振响应的大小;在本文各种工况下,Davenport谱所得背景响应基本上略小于Simiu谱结果,但Davenport谱所得前2阶模态力谱在结构对应频率位置的谱值均大于Simiu谱所得模态力谱,故前者所得共振分量和总脉动响应均偏大。To clarify the wind-induced along-wind responses of high-rise structures under different wind spectrums,the Davenport and Simiu spectrums are selected and the wind-induced vibrations of a single-column lightning rod structure under several conditions are calculated in frequency domain based on the random vibration theory.Then,a new method evaluating the responses is proposed which employs the modal force spectrums instead of the wind spectrums directly.Because the Simiu spectrum varies with height,it could not be compared with the Davenport spectrum.However,the modal force spectrum could cover the whole fluctuating wind field of the structures,so it could be employed to compare the responses of different wind spectrums if only one mode controlling the response.For the example of a high-rise structure,it can be observed that the background responses of the Davenport spectrum usually slightly less than those of the Simiu spectrum.However,the values of the first two modal force spectrums got from Davenport spectrum are always greater those got from Simiu spectrum at the corresponding frequencies,so the resonant responses and the total fluctuating responses got from Davenport spectrum are greater.

关 键 词：DAVENPORT谱 Simiu谱 避雷针 风振效应 风谱特征 模态力谱 

分 类 号：TU311.3[建筑科学—结构工程] TU392.3