文献类型：期刊文献

英文题名：Design of amplitude and phase demodulation circuit based on TMR and detection of crack defects

作者：Yang, Yan[1]; Hu, Minghui[1]

机构：[1] Key Laboratory of Pressure Systems and Safety, East China University of Science and Technology, Shanghai, 200237, China

年份：2022

卷号：12252

外文期刊名：Proceedings of SPIE - The International Society for Optical Engineering

收录：EI(收录号：20222612300868)

语种：英文

外文关键词：Aluminum alloys - Crack detection - Eddy current testing - Optical variables measurement - Phase modulation - Timing circuits

摘要：In order to demodulate the voltage signal output by the eddy current detection sensor, an amplitude and phase demodulation circuit suitable for the low frequency range (20k) is designed, and the phase shift error is controlled within ±0.5%. The amplitude-phase demodulation circuit is used in a self-designed tunnel magnetoresistive sensor (TMR) probe based on magnetic shielding, and the detection of crack-type defects of different sizes on the surface of 6061 aluminum alloy plate is realized. The experimental results show that the amplitude and phase demodulation circuit can effectively demodulate the amplitude and phase information of the signal to be measured, and the phase information is hardly affected by the excitation current and is sensitive to the excitation frequency. The optimal excitation frequency for phase orientation in the experiment is 5kHz. The demodulated amplitude and phase information can characterize the crack defects of different lengths (10mm, 20mm, 30mm) and different depths (1-5mm) on the 6061 aluminum alloy plate. Whether it is the voltage amplitude or the phase result, when the defect depth is within 3mm, the output is approximately linearly related to the defect depth. ? 2022 SPIE.