移动荷载下高速铁路简支梁桥消振机理频域分析  

Frequency-domain analysis of vibration cancellation mechanism for a simply supported bridge of high-speed railway under moving loads

作　　者：李锦华[1] 李添艺 吴亮秦 张焕涛 LI Jinhua;LI Tianyi;WU Liangqin;ZHANG Huantao(Department of Civil Engineering,East China Jiaotong University,Nanchang 330013,China)

机构地区：[1]华东交通大学土木建筑学院,南昌330013

出　　处：《振动与冲击》2021年第16期287-293,共7页Journal of Vibration and Shock

基　　金：国家自然科学基金(11962006)。

摘　　要：桥梁动力响应问题随着列车运营速度的不断提高也愈加明显。为了保证列车在高速运行下引起的桥梁动力响应在安全范围内,则对建立列车运营时速与桥梁位移响应幅值之间的关系显得尤为重要。因此,针对多个移动荷载激励下桥梁消振机理提出了一种行之有效的频域分析方法。该方法首先对桥梁运动方程采用傅里叶变换,得到移动荷载匀速通过桥梁时的移动荷载傅里叶幅值谱;然后基于移动荷载傅里叶幅值谱,建立了移动荷载速度与桥梁消振效应之间的关系;最后以高速铁路简支梁为例验证了理论推导及分析的正确性和速度公式的有效性。结果表明:由频域得到的移动荷载傅里叶幅值谱能有效反映桥梁自由振动,与时域内得到的桥梁自由振动幅值响应规律一致;非等间距移动荷载作用下桥梁发生消振现象时,第一类移动荷载消振速度仅与桥梁跨度、基频有关,第二类移动荷载消振速度与桥梁基频、移动荷载间距有关。The problem of bridge dynamic response becomes more and more obvious with the continuous improvement of train operating speed.In order to ensure that the bridge dynamic response caused by the train under high-speed operation is within the safe range,it is particularly important to establish the relationship between the train operation speed and the bridge displacement response amplitude.Therefore,an effective frequency-domain analysis method was proposed for the vibration cancellation mechanism of railway simply supported bridge under multiple moving loads.In this method,firstly,the Fourier transform was applied to the motion equation of the bridge to obtain the Fourier amplitude spectrum of moving loads for the case that the moving loads pass through the bridge at a uniform speed.Then,based on the Fourier amplitude spectrum,the relationship between the moving load speed and the bridge vibration cancellation effect was established.Finally,taking the simply supported beam of a high-speed railway as an example,the correctness of theoretical derivation and analysis and the effectiveness of speed formula were verified.The results show that:the Fourier amplitude spectrum of moving loads obtained in the frequency domain can effectively reflect the free vibration of bridge,which is consistent with the amplitude response of the free vibration of the bridge obtained from the time-domain;when the bridge vibration cancellation phenomena occur under non-equidistant moving loads,the first kind of the moving load cancellation speed is only related to the bridge span and fundamental frequency,and the second kind is related to the bridge fundamental frequency and the moving load spacing.

关 键 词：消振机理 移动荷载 简支梁桥 高速铁路 频域分析法 

分 类 号：U213.213[交通运输工程—道路与铁道工程]