新型PVDF声发射传感器的设计方法及应用

基于声发射技术研制了一种新型PVDF压电传感器。介绍了声发射传感器的结构、工作原理以及声发射传感器压电元件、背衬材料、声匹配层和前置放大器接口电路设计对传感器灵敏度、分辨率和信噪比的影响。利用美国物理声学公司声发射信号数据采集处理DiSP系统进行了断铅信号采集试验。测试结果表明：设计的新型PVDF声发射传感器对断铅信号具有宽频带响应。应用研制的新型PVDF声发射传感器、数字示波器和计算机组成的数据采集处理系统对4M20氮氢气压缩机六段排气阀进行了状态监测，结果表明新型声发射传感器能够用于设备状态监测，设计方法可行。

Application and Design Method of Late-model PVDF Acoustic Emission Sensor

The design of a late-model PVDF acoustic sensor based on the acoustic emission techniques is described detailedly in this paper,including the operating principle and the structure of the sensor,and the influence of piezo element,backing material,acoustic matching layer and pre-amplifier on the sensitivity,resolution and signal to noise ratio(SNR) of the sensor.Using this sensor,experiment of pencil lead break has been conducted by DiSP Acoustic Emission Workstation,and condition monitoring test of six-stage outlet valve of 4M20 nitrogen and hydrogen compressor has been performed by the data acquisition and processing system,which consists of the digital oscilloscope and computer.The sensor,with single resonant frequency response mode,has a broad-band response to the acoustic emission signals generated by the pencil lead break;the sensor can also perceive the weak signals existed in abnormal work condition state of compressor outlet valve.Therefore it can be applied to monitor the working condition of equipment and the design method is acceptable.