Application Of EMD Method In Health Parameters Of Dynamic Strain Of Bridge

The health monitoring of small and medium bridge has attracted much attentions from the academia and engineering communities in recent years.There is an urgent need for proposing effective analytical methods to deal with the signal acquisition and processing of the monitoring system and establishing the relationship between monitoring results and health state of bridge.The main contents of this paper are as following:(1)The Empirical Mode Decomposition(EMD)deconstruction method is introduced,and the extreme point prediction method is used to solve the end point effect.A discussion on three different combinations of EMD method is conducted,and the optimal combination of each method is obtained by processing the simulation signal in MATLAB software.EMD data processing method which is suitable for the health monitoring system is presented,according to the measured dynamic strain signal and the comparison result of different signal-noise-ratios(SNRs).(2)A health monitoring system for medium and small bridges is introduced.Driving test is conducted to test the performance of signal acquisition and transmission of the system,which is established on actual bridge.Relationship between temperature and strain has been established statistically by previous data.The dynamic strain,eliminated of temperature strain through the relationship,is processed and analyzed with the EMD method.(3)Fitting the parameters of dynamic strain of bridge after calculating them through the methods proposed in the paper.Relationship between the parameters and the health state of the bridge is established by the setting of initial interval of strain health parameter's threshold after integrating fitting curves and distribution law of historical data.