Propagation Characteristics Of Acoustic Emission In Vertical And Horizontal Direction And Damage Localization Method Of Parallel Wire Cable

Parallel steel wire cables are one of the most important stress-bearing components in cable-stayed bridges.Once the cables are damaged,the safety,applicability and durability of the bridge will inevitably be reduced.Therefore,non-destructive monitoring technology is adopted for health monitoring.Vital.This paper uses COMSOL Multiphysics software to establish a physical model of acoustic-structure coupling,and studies the propagation path of acoustic emission waves in parallel steel wire bundles.A parallel wire bundle test system based on acoustic emission was constructed,and the longitudinal and lateral propagation characteristics of the acoustic emission wave in the parallel wire bundle were experimentally studied.Finally,a positioning algorithm was proposed and verified by experiments.The spatial positioning of parallel wire bundle damage and broken wires.The main research contents and results of this paper are as follows:(1)In order to determine the propagation path of the acoustic emission wave on the parallel wire bundles,a visualization study of the propagation process of the acoustic emission wave was carried out.Using the acoustic-structure multi-physics module in the COMSOL software,a physical model of acoustic emission waves propagating in parallel steel wire bundles was established,the propagation process of simulated acoustic emission waves in parallel steel wire bundles was visualized,and the steel wires at different moments were analyzed.Surface displacement,sound pressure in the air domain,and force between steel wires.The results show that the acoustic emission wave generated by the damage of the steel wire first propagates along the length of the steel wire and then radially;the energy of the acoustic emission wave presents an alternating oscillation propagation phenomenon between the steel wires(2)An acoustic emission test system was built to study the propagation of acoustic emission signals on parallel wire bundles.Results show that the increase in the propagation distance not only attenuates the amplitude of acoustic emission signal but also changes the energy proportion of the normalized value of different frequency band components of the signal.An oscillation phenomenon of wave energy transfer among the wires in parallel steel wire bundles is also observed.(3)In this paper,two kinds of acoustic emission attenuation tests were carried out in different directions of parallel steel wire cable cross-sections.In the two kinds of attenuation test,wide-band acoustic emission sources were simulated by pencil broken lead,and single-frequency acoustic emission sources were simulated by sinusoidal pulse signals.The relationship of the transverse propagation attenuation law of the acoustic emission signal on the parallel steel wire cable with both propagation length and direction was then examined by conducting parameter and waveform analyses of the collected acoustic emission signals.The universality of the attenuation law in the cable was also discussed.Results show that the attenuation law is related to both propagation length and angle.When the broadband acoustic emission signal propagates laterally on the parallel steel cable,various amplitude attenuation rates are observed across different propagation directions.Meanwhile,extending the propagation length decelerates the signal amplitude attenuation,thereby leading to the disappearance of the high-frequency component of the signal and the distortion of the signal itself.The attenuation law of the single-frequency acoustic emission signal in the parallel steel cable is related to not only the propagation and angle but also to the magnitude of the simulated acoustic emission source frequency(4)Based on numerical simulation and the acoustic emission attenuation testing,acoustic emission signal propagation path in the parallel wire beam and transmission attenuation characteristics,this paper puts forward a applicable parallel wire bundle of precision positioning algorithm,and then based on the acoustic emission monitoring of parallel wire bundle of the tension test,acoustic emission signals were collected for wavelet transform,get different sensors to collect wire fault signal delay,combined with the parallel wire bunch of dispersion curve and the time-frequency diagrams get different frequency of the acoustic emission signal propagation speed,the broken wire position obtained by calculation,the localization algorithm is verified.The results show the feasibility of the proposed parallel wire bundle positioning algorithm.