基于连续跳车激振的大跨度桥梁阻尼识别研究

发布时间：2018-04-17 23:03

  本文选题：大跨桥梁 + 阻尼　； 参考：《铁道科学与工程学报》2017年08期

【摘要】：提出一种基于连续跳车激振的大跨度桥梁阻尼识别的强迫振动法。该方法利用"共振"原理,让车辆以合适速度连续驶越障碍物使主梁经受与桥梁某阶频率相同的周期性脉冲荷载,使桥梁产生较大振幅的振动,从而增强测试信号的信噪比。给出基于连续跳车激振的结构阻尼比识别的基本理论,并以一大跨度悬索桥为例进行动力学仿真。复模态分析表明,当车辆固有频率是桥梁某阶受测模态频率的5倍以上时,车辆振动对受测模态阻尼比影响很小。采用连续跳车激励,当相邻障碍物的间隔△x与行车速度V和受测模态的固有周期T之间满足△x=VT,可以激振起桥梁大幅振动。当噪信比较小时,可以较准确地识别1阶反对称模态阻尼比;随着信噪比的降低,阻尼比识别结果精度有所降低。
[Abstract]:A forced vibration method for identifying the damping of long span bridges based on continuous jump vibration is proposed.By using the principle of "resonance", the vehicle can continuously drive over the obstacle at a suitable speed to make the main beam undergo the periodic pulse load with the same frequency as the bridge, so that the bridge produces a large amplitude of vibration, thus enhancing the signal-to-noise ratio of the test signal.The basic theory of structure damping ratio identification based on continuous jump vibration is presented, and the dynamic simulation of a long-span suspension bridge is carried out.The complex modal analysis shows that the vehicle vibration has little effect on the damping ratio of the tested modes when the natural frequency of the vehicle is more than 5 times of the measured modal frequency of the bridge.Using continuous jump excitation, when the interval x of adjacent obstacles and the driving speed V and the natural period T of the measured mode satisfy x / V _ T, the bridge can be excited to vibrate greatly.The first order antisymmetric mode damping ratio can be accurately identified when the noise signal ratio is small, and the accuracy of the identification result is decreased with the decrease of signal-to-noise ratio (SNR).
【作者单位】： 湖南大学风工程与桥梁工程湖南省重点实验室;湖南省交通规划勘察设计院;
【基金】：国家自然科学基金资助项目(51422806,51278189)
【分类号】：U441.3
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本文编号：1765678