CAJ | 학술논문

针对现代工业与安全检测中对非铁磁性工件的表面及近表面缺陷检测需要，基于涡流无损检测原理，采用灵敏度高、体积小、工作频率范围宽(0Hz到MHz)的GMR传感器，结合基于单片机STM32的直接数字频率合成(DDS)信号产生方法及锁相技术研制了一套涡流无损检测系统。实验结果表明该基于 GMR传感器的无损检测系统能够较好的检测出铝板试件表面及表面下2 mm处缺陷的存在，多道扫描结果可清晰判别出缺陷的位置和大小，该系统可以准确完成对导电材料表面及近表面的无损检测。
침대현대공업여안전검측중대비철자성공건적표면급근표면결함검측수요，기우와류무손검측원리，채용령민도고、체적소、공작빈솔범위관(0Hz도MHz)적GMR전감기，결합기우단편궤STM32적직접수자빈솔합성(DDS)신호산생방법급쇄상기술연제료일투와류무손검측계통。실험결과표명해기우 GMR전감기적무손검측계통능구교호적검측출려판시건표면급표면하2 mm처결함적존재，다도소묘결과가청석판별출결함적위치화대소，해계통가이준학완성대도전재료표면급근표면적무손검측。
For the need of modern industrial safety testing of surface and near-surface defect detection of non-ferromagnetic workpieces,based on the principle of eddy current testing and the giant magneto-resistive (GMR)sensors,Nondestructive Testing method is an effective eddy current testing technique which has a lot of advantages such as the high sensitivity,high resolution, wide operating frequency range (0 Hz to MHz),small sensor volume and simple signal processing circuit and easy integration.In this paper,one simple and excellent GMR-based eddy current system is designed.The GMR sensor with high sensitivity of 30mv/Oe,the microcontroller STM32-based direct digital synthesis signal generation method and phase-lock technique are used in this system.The results show that the GMR-based eddy current system can detect the presence of the defective on the surface or under the aluminum plate surface 2 mm,the shape and location can be known by multi-channel scanning.The system can accurately perform non-destructive testing of surface or near-surface defect detection for nonmagnetic metals.