基于移动传感的桥梁自动模态参数识别

Automatic modal parametric identification of bridge based on mobile sensing

提出一种基于移动传感的桥梁自动模态参数识别方法。移动传感单元包括一个动力车和一个刚性小拖车,动力车搭载了数据采集和传输设备以及北斗授时模块,刚性拖车搭载加速度拾振器,动力车与拖车的连接具有良好的隔振效果,有效获取桥梁结构本身不同位置的振动信号。模态试验时,移动传感单元依次自动获取不同测点的结构振动信息,通过北斗授时模块实现与固定参考单元获取的振动信息相位时间同步。基于随机子空间的自动模态参数识别方法可以快速从固定参考单元与移动传感单元获取的振动信息中提取结构模态信息。该方法可以获取较高的空间分辨率结构振动信息,进而获取准确的结构振型信息。将移动传感应用于一座下承式系杆拱桥,取得了优良的模态识别效果。

Here,an automatic modal parametric identification method of bridge based on mobile sensing was proposed.The mobile sensing unit could include a power car and a rigid small trailer.The power car was equipped with data acquisition and transmission equipment and Beidou time service module.The rigid trailer was equipped with vibration acceleration transducers.The connection between the power car and the trailer could have good vibration isolation effect,and effectively obtain vibration signals at different positions of bridge structure itself.During modal tests,the mobile sensing unit could automatically obtain bridge structural vibration information at different measured points in turn,and the phase time synchronization could be realized between bridge vibration information collected on the mobile sensing unit and that obtained on a fixed reference unit through Beidou time service module.The automatic modal parametric identification method based on the stochastic subspace method could quickly extract structural modal information from vibration information obtained both on the fixed reference unit and the mobile sensing unit.It was shown that the proposed method can obtain structural vibration information with higher spatial resolution,and then obtain accurate structural vibration modal shape information.The mobile sensing unit was applied in modal tests of a through tied arch bridge to acquire good modal identification effect.