江阴大桥实测数据时间同步分析

Time synchronization analysis of monitoring data of Jiangyin bridge

针对江阴大桥结构健康监测系统因缺陷导致加速度信号间存在时间不同步的问题,提出了相关系数的时域校准方法来纠正不同位置处加速度间的时间延迟。任意选择某一处的加速度数据作为参考信号,其余的加速度作为时间平移信号。然后对平移信号相对参考信号进行时间平移。对于每一次时间平移,分别利用相关系数算法求解参考信号与平移信号的相关系数。当信号间的相关系数达到最大值时所对应的时间即为两者的实际延迟时间。为验证该算法的准确性,对时间同步后的数据进行了模态分析。结果表明:相关系数的时域校准方法用于识别时间延迟得到了较为理想的效果。

As for the time synchronization problem of acceleration signals due to the defects in the structural health monitoring system of Jiangyin bridge,a time domain calibration method for the correlation coefficient is proposed to calibrate the time delay between different positions of the bridge.One of the accelerations is randomly chosen as the reference signal and the others are used as time shift signals.The time axe of each time shift signal is then shifted relative to that of the reference signal by a time instant.For each time instant,the correlation coefficient algorithm is used to calculate the correlation coefficient between the reference signal and the time shifted signal.When the correlation coefficient reaches the maximum value,the corresponding time is considered as the actual time delay.To further verify the accuracy of the algorithm,a modal analysis of aligned accelerations is conducted.The results show that the correlation coefficient algorithm can be used to compute the time delay with reasonable accuracy.