针对传统的压电超声技术应用在铝合金厚板缺陷检测中存在的不足,设计了一种基于电磁超声的铝合金厚板缺陷检测装置.该装置具有无需声耦合剂,检测效率高等优点.装置主要包括电磁超声探头、高频大功率发射电路、低噪声高增益接收电路、FPGA(现场可编程门阵列)及其外围电路和S3C2440液晶控创电路.在铝制标准试件上进行测试试验表明:该装置能够有效检测出直径1.2mm、埋深10～60 mm的平底孔缺陷,符合铝合金厚板缺陷检测需求,具有良好的工程应用价值.%In view of insufficiency of traditional piezoelectric technology in the flaw detection field of thick aluminum plate,a flaw detection device for thick aluminum plate baaed on electromagnetic acoustic transducer (EMAT) was designed. It had several distinct advantages including operation without couplant and high efficiency and so on. The device mainly includes an EMAT probe,a high frequency and high power transmitter,a low noise and high gain receiver.FPGA and its peripheral circuits and a liquid crystal display control circuit based on S3C2440. Experiment result shows that the device can effectively delect flat bottomed holes whose diameter is 1.2 mm,and the depth ranges from 10 mm to 60 mm,which meets the flaw detection requirements and has great potential in engineering applications.
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