摘要
针对传统远场涡流检测方法对铁磁性管道内外壁缺陷灵敏度相同,无法有效区分缺陷在管道内壁还是管道外表面的问题,提出了采用具有丰富频率成分的脉冲激励信号取代传统的远场涡流中正弦信号激励的方法。采用小波去噪方法滤除检测数据中的信号噪声;研究了将检测线圈分别置于近场区、过渡区和远场区时的信号时域特性与管壁伤的关系;进行了针对管道管壁内外相同宽度不同深度缺陷的检测试验,结果表明采用脉冲激励作为激励源并综合运用过渡区的检测信号的幅值和过零时间特征能够有效地区分管壁内外全周向的缺陷。
In view of the traditional remote field eddy current technique for ferromagnetic tube having the same sensitivity of inner and outside walls defect, unable to distinguish the defects in the inner wall or in the outer surface, this paper adopt with abun- dant frequency components of the pulse signal to replace the traditional remote field eddy current sinusoidal excitation signal. Using the methods of wavelet denoising to filter acquired signal and process the data. This paper studied the relationship between the tube wall defects and signal time-domain characteristics when the detector coil was placed in the direct zone, transition zone and remote field zone. Conduct experiments to acquire data about different depth defects in the inside or outside of the walls, the results show that using the pulse signal as excitation source and characteristics about the detect signal amplitude and zero-crossing time can effectively distinguish between the inner and outer circumferential direction tube wall defects.
出处
《仪表技术与传感器》
CSCD
北大核心
2012年第11期141-144,共4页
Instrument Technique and Sensor
基金
国家自然科学基金仪表专项资助项目(60927004)
国家自然科学基金资助项目(61141004)
国家自然科学基金资助项目(61141004)
十二五国家科技部支撑计划资助项目(2011BAK06B01-03)
关键词
远场涡流
脉冲涡流
管壁缺陷
小波去噪
管道检测
remote field eddy current
pulsed eddy current
ferromagnetic walls defect
wavelet denoising
ferromagnetic tube testing