| Metal structural parts are widely used in transportation,shipping,aerospace and construction,so it is very important to monitor their structural health.Acoustic emission,as an important means of structural health monitoring technology,can effectively predict the remaining life of structural components by processing and analyzing the signal data collected by acoustic emission sensors.In the process of structural health monitoring,different applications of acoustic emission sensor resonance frequency requirement is different,you can choose different resonance frequency sensitive element of the design to meet the demand of scene monitoring,based on the research hot spot,this article through to the resonance frequency of the sensor is studied and developed for metal structural health monitoring of the acoustic emission sensor.The main research contents of this paper include the following points:（1）The characteristics of acoustic emission signals of crack defects in metal materials were analyzed,and the acoustic emission sensor structure was designed with PZT-5H piezoelectric ceramics as the sensitive element and alumina as the sound matching layer.Based on the resonant frequency and acoustic impedance matching theory,the material and parameter size of each component were analyzed.The sensor shell is designed with chamfering,and the silencing cotton is bonded inside,which can effectively suppress the influence of noise.（2）Through various simulation types in the finite element analysis,the performance of key components in the piezoacoustic emission sensor is simulated,and the response characteristics of sensor models with different parameters and sizes are evaluated.The resonance frequency of the sensor model under the design parameters is within the design requirements,which verifies the correctness of the theoretical analysis.（3）The acoustic emission structural health monitoring experimental platform was set up,and the performance of piezoelectric acoustic emission sensor in the structural health monitoring system was tested through lead breaking test,centralized location test and fatigue load test.The test results show that the piezoacoustic emission sensor resonance frequency is152 k Hz,resonance point sensitivity is 70 d B,it has a good acoustic response to a variety of metal materials,the sound source positioning error is less than 5%,the design meets the performance requirements estimated. |
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