Research On Micro Inertial Sensing Technology For Bridge Vibration With Its Features

Bridge is an essential component of modern transport systems.During the service of a bridge,vehicle and environmental excitation are the main factors in generating bridge vibration.The installation of accelerometers on bridges for vibration monitoring allows for the assessment of the real-time state of the bridge structure.This paper focuses on the use of acceleration excitation response signals measured by accelerometers installed on bridges,and then analyses the acceleration signals to study the vibration characteristics of bridges,to achieve the purpose of monitoring bridges using acceleration sensing technology.The main research elements are as follows:(1)Study the bridge vibration-deformation displacement reconstruction algorithm.The quadratic integration algorithm is sensitive to the low frequency noise of the displacement and the drift of the displacement baseline after integration.In this paper,the bridge displacement reconstruction technique is studied by using singular spectrum analysis(SSA)combined with Tikhonov regularization method.The SSA method is first used to denoise the vibration signal,and then a regularization factor is added to the data to weaken the effect of the initial value of the integration on the reconstructed displacement.Experiments show that the displacement signal reconstructed using the displacement integration algorithm has a correlation number level of about 97% with the simulated original signal,verifying that SSA-Tikhonov can perform displacement reconstruction better.(2)Study of bridge multi-event vibration time-frequency extraction method.For the problem of difficult extraction of signal characteristics during multi-event monitoring,the signal is decomposed using the variational mode decomposition(VMD)method,and a multi-objective optimization-based VMD parameter acquisition method is adopted to improve the problem of difficult determination of parameters in VMD decomposition.VMD has more advantages than empirical mode decomposition(EMD)in terms of decomposition accuracy and resistance to noise interference,replacing EMD in Hilbert-Huang transform(HHT)with VMD.The bridge signal is processed by using the variable mode decomposition combines the Hilbert-Huang transform method.Through the analysis of the measured data,the VMD-HHT method can better achieve the time-frequency extraction of bridge multievents for the multi-event vibration monitoring of bridges.(3)Study of vehicle-bridge coupling vibration and decoupling problems.The vehiclebridge coupling vibration affects the extraction of bridge self-oscillation frequencies,and the VMD method is used to analyze the third-order self-oscillation frequencies of bridges at different vehicle speeds.The results show that in the vehicle-bridge coupled vibration system,the deviation of the VMD identification of the self-oscillation frequencies of the bridge at different vehicle speeds ranges from 0.012 Hz to 0.023 Hz,and the maximum error of the self-oscillation frequency identification is 2.34%,and the VMD can better separate the thirdorder self-oscillation frequencies of the bridge.In addition,the VMD-HHT can be used to analyze the location of bridge damage,so the VMD-HHT can also be used to identify the location of bridge damage.