| 涡流探头提离效应的理论分析与实验研究 |
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| 引用本文： | 张玉华,孙慧贤,罗飞路. 涡流探头提离效应的理论分析与实验研究[J]. 电机与控制学报, 2009, 13(2) |
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| 作者姓名： | 张玉华 孙慧贤 罗飞路 |
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| 作者单位： | 国防科学技术大学,机电工程与自动化学院,湖南,长沙,410073 |
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| 摘 要： | 推导了线圈置于有限厚度的金属平板上方时其阻抗计算的级数表达式,并以此为基础分析了由线圈的提离改变所引起的线圈阻抗的变化特征.同时采用有限元法对导体平板上有缺陷存在时的复杂三维涡流问题进行计算求解,进一步分析了提离变化对缺陷所引起的线圈阻抗变化的影响.结果表明提离增加会显著降低缺陷信号的幅值,但并不影响缺陷信号和提离轨迹之间的相位差,通过分析相位差随检测频率的变化规律发现:存在一个合适的频率可使缺陷信号和提离干扰之间出现90°的相位差.实验数据说明了阻抗计算模型及其理论分析的正确性,其结论为实际检测中利用相位旋转及信号增强技术消除提离干扰提供了有价值的理论参考.
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| 关 键 词： | 涡流检测 提离效应 阻抗计算 有限元法 相位差 |
Theoretical and experimental analysis of lift-off effects on probe impedance in eddy-current testing |
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| ZHANG Yu-hua,SUN Hui-xian,LUO Fei-lu. Theoretical and experimental analysis of lift-off effects on probe impedance in eddy-current testing[J]. Electric Machines and Control, 2009, 13(2) |
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| Authors: | ZHANG Yu-hua SUN Hui-xian LUO Fei-lu |
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| Affiliation: | College of Mechatronics Engineering and Automation;National University of Defense Technology;Changsha 410073;China |
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| Abstract: | The impedance of a probe-coil above a conductive plate with finite thickness was derived and expressed in series expansion,and then the impedance characteristics of the coil due to lift-off variation were analyzed.Furthermore,three-dimension eddy-current problem for a coil above the plate with a defect was calculated by finite element method.Effects of lift-off on coil impedance change produced by a defect were investigated.The results show that amplitude of defect signal is adversely affected by lift-off v... |
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| Keywords: | eddy-current testing lift-off effect impedance calculation finite element method phase difference |
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