Design Of Wireless Acoustic Emission Bridge Structural Health Detector Based On FPGA

In the transportation system,the bridge is an important link.With the continuous improvement of China's transportation system.The safety of bridges is also more and more important.The use time of modern bridge design is generally more than a few decades,and it is exposed for a long time.In harsh environments,erosion causes aging of the material.Coupled with excessive use,geological disasters and other factors,the bridge structural system is damaged to varying degrees,resulting in weakened resistance to external forces.In severe cases,it can lead to the collapse of the bridge.And even worse,as a result of major casualties,it can be seen that the detection of bridge structure health is very important.Different from traditional non-destructive testing,a new non-destructive test has been proposed.It is a passive detection method that does not require an external excitation source.The detected signal originates from the measured entity itself and the new non-destructive test can detect the dynamic defect of the material.Random feature signals of materials are collected and feature values are extracted to analyze the damage of the bridge.Therefore,it is very important to acquire acoustic emission signals.Based on this,this paper designs a wireless acoustic emission detector based on FPGA and can be used for bridge structure health detection.The detector has high sampling rate,multi-channel,wireless transmission and other features.In this paper,Cyclone IV series FPGA device developed by Altera Corporation is used as the core controller of the wireless acoustic emission detector.The random feature signal is collected by the high-speed AD module.After the related data is sorted by the FPGA,the data is stored in the SD card.Then,the data collected and stored in the SD card is controlled by the FPGA and sent to the PC-side host computer for display and storage by the wireless serial port.This paper firstly introduced the overall design of the system,and determines that the number of signal acquisition channels is four channels.Then,it is introduced the design of the system's hardware module circuit,and given a specific hardware circuit,including power supply,FPGA controller,AD acquisition,AD voltage conversion,small signal preamplifiercircuit,then introducing FPGA programming and virtual instrument LabVIEW software design,the use of hardware description language Verilog HDL FPGA software design.The functions implemented mainly include 4-way AD acquisition control,threshold settings,signal storage and superior Machine communication.Finally,the system was jointly tested on the hardware test platform built.The analog single-channel data acquisition experiment and the4-channel acoustic emission synchronization signal acquisition experiment were performed.Finally,the acoustic emission detector was applicable to bridge structure health detection.