Research On Health Monitoring Of Interface Damage Of Steel Structure On Piezoelectric Ceramic Transducers

In recent years,with the vigorous development of steel bridge,the health detection technology of steel structure has been widely studied by many scholars.In practical engineering application,steel bridge is affected by vibration impact,fatigue load,forced vibration and other environmental factors.The interface of steel structure often has a certain degree of damage,which has a very adverse impact on the safe operation of the structure.In this paper,the advantages of piezoelectric ceramics,such as low cost,small volume,wide response frequency domain and embeddability,are brought into full play.(1)Aiming at the problem of interface damage in steel truss arch structure,a health detection method based on piezoelectric wave method is proposed.The triangular arch of steel truss used in tunnel supporting slot is used as experimental specimen,and the interface damage between joint plate and chord bar is simulated by bolt loosening on the connecting plate.At the same time,static loading is carried out according to the actual situation of the project.The piezoelectric actuator is arranged on the node board and the sensor is arranged on the chord bar to receive the signal.The signal under different damage conditions is collected.The results show that the change of vertical displacement acquired by the traditional stiffness analysis method in damage state I is almost the same as that in healthy state,while the change of signal amplitude in damage state I can be clearly detected by the piezoelectric material detection method,which indicates that the piezoelectric wave method can be used to detect the steel truss arch structure.Sensitivity.At the same time,with the further increase of damage degree,the amplitude of signal collected by piezoelectric ceramic sensor is also decreasing,which further validates the feasibility and effectiveness of piezoelectric wave method for detecting the interface damage of steel truss arch structure.(2)To solve the problem of interface damage in steel-concrete composite structures,a health monitoring system based on piezoelectric wave method is proposed.The interface damage of steel-concrete composite structure was simulated by bolt shear bond tightening in different degrees.In the experiment,piezoelectric ceramic sheets as actuators are pasted on the flange of steel beams,and smart aggregates as sensors are embedded in concrete flange plates to record the changes of response signals received by sensors under different damage conditions.Finally,the response signals are analyzed by time-domain signals,frequency domain signals and wavelet packet theory.The experimental results show that the time-domain signal,frequency-domain signal and wavelet packet energy amplitude of piezoelectric ceramic sensor decrease obviously when the structure is damaged;with the further increase of damage,the amplitude of signal in time-domain signal does not change significantly,but can be obtained from time-domain signal and wavelet packet energy analysis.Furthermore,the trend of decreasing amplitude is found,which shows that time domain signal analysis method and wavelet packet energy analysis are more sensitive to interface damage detection in steel-concrete composite structures.Thus,the effectiveness and feasibility of interface damage detection in steel-concrete composite structures based on piezoelectric ceramics are further illustrated.