基于反射与折射理论的电涡流检测探头阻抗解析模型

应用电磁波的反射与折射理论建立了多层导电结构电涡流检测探头阻抗解析模型.电涡流检测中空间电磁场可看作线圈激励场与涡流场的叠加，而涡流场是线圈激励场的反射与折射效应，因此应用线圈激励场的级数型解析解和电磁波的反射与折射理论推导了级数型探头阻抗解析解.最后，比较了推导的级数型与传统的积分型探头阻抗解析解的计算结果，并进行了实验验证.计算结果与实验结果基本吻合，表明推导的级数型探头阻抗解析解是正确的，且与积分解析解相比具有不需要确定积分上限、耗时少、计算精度容易控制等优点. 关键词： 电涡流检测 多层导电结构 反射与折射理论 探头阻抗

Analytical modeling for probe impedance using reflection and transmission theory in eddy current testing

The analytical model of probe impedance due to multilayered conductive structures is established using the reflection and transmission theory of electromagnetic waves in eddy current testing. The electromagnetic field in the region under considecation consists of the excitation field of the coil and the eddy current field. The eddy current field is regarded as the combination of the reflection and transmission of the excitation field. Therefore, the probe impedance is analytically modeled by applying the series-form representation of the excitation field and the reflection and transmission theory of electromagnetic waves, thus resulting in a series-form expression. Finally, the calculated results from the typical integral-form and developed series-form expressions were compared, and experiments were carried out. The good agreement between the calculated and experimental results justifies the presented analytical model. In comparison with the infinite integral of probe impedance, the series-form expansion has advantages of not needing the determination of the integral upper limit, saving time and easy control of the error.