Eddy current testing methods to estimate the anisotropic electrical conductivity of multidirectional carbon fiber reinforced plastics are proposed in this work. Finite element analysis was performed to investigate the contributions of the three-directional conductivities to the coil impedance. The coil impedance variation was expressed as an approximate function with respect to the anisotropic conductivity using the response surface methodology. Three proposed methods were applied to estimate the conductivity from the measured coil impedance and the estimated conductivities were then compared with the conductivities measured using a four-probe method. Use of the response surface enabled prediction of the lower and upper limits of the conductivity while taking the scatter of the electrical properties in the tested material into consideration. The conductivity range was predicted correctly using the proposed methods. There was a trade-off relationship between the accuracy and the simplicity of these estimation methods.

在这项工作中，提出了用于估计多向碳纤维增强塑料各向异性导电性的涡流测试方法。进行了有限元分析，以研究三方向电导率对线圈阻抗的影响。使用响应表面方法，将线圈阻抗变化表示为相对于各向异性电导率的近似函数。应用了三种建议的方法，从测量的线圈阻抗估算电导率，然后将估算的电导率与使用四探针法测量的电导率进行比较。使用响应表面可以预测电导率的下限和上限，同时考虑到测试材料中电学特性的分散性。使用提出的方法可以正确预测电导率范围。这些估算方法的准确性和简便性之间存在折衷关系。