Research On Monitoring System Of Concrete Damage Source Based On Acoustic Emission

It is critical to supervise the fitness condition of beton construction in real timeand provide damage source information in time to give corresponding protection to structures.As a commonly used non-destructive testing technology for concrete structure health monitoring,sound transmission supervision technology can supervise the condition of defect activitieswithin the construction without interruption,detect the location,size and type of structural defects,and play an extremely key role in structural monitoring.In this paper,the acoustic emission acquisition system and damage source localization of concrete structures are studied,and an acoustic emission acquisition system based on the damage source of concrete structure is designed by comparing the research status at home and abroad,and the Gaussian Newtonian positioning algorithm is used to accurately locate the damage source.The acquisition system consists of signal conditioning part,analog-to-digital conversion part,FPGA control part,data transmission part,and host computer software part.FPGA,as the primary command chip of the system,realizes the sampling control of the AD module.After the data cache is completed,the data is transmitted to the upper machine through the Ethernet UDP protocol.The host computer is designed by LabVIEW,and the collected data is displayed for waveform display and feature parameter extraction.The threshold noise derease of the acquired signal is proceeded by the small wave base,and the COIF2 small wave base is designated to decomposition the number of layers 6 to retain the originalsignal characteristics relatively completely.The piezoelectric acoustic module of COMSOL software was used to create a concrete structure model,and the Gaussian Newtonian positioning algorithm was used to co-simulate the localization of the damage sources set internally,and the relative positioning deviation was 1.3%.Then,the built hardware test platform is used to verify the acoustic emission acquisition system,and the relative error of the test data is-0.6%.Finally,the damage source of the concrete sheet was measured,and the time parameters of acoustic emission signal were measured as 50,HDT as100 and HLT as 250.The measured wave velocity value was 3620.9,and the average relative error value of positioning was 2.1%.Test verification indicates that the overall system can come true the data acquisition and visualization of multi-channel acoustic emission signals.The Gaussian Newton positioning algorithm is used to locate the broken lead point of the concrete sheet,which can accurately locate the coordinates of the damage source and meet the needs of accurate positioning of the concrete damage source.