三维探伤涡流场的研究与线圈阻抗的计算

Approach to Three-dimensional Eddy Current Problems and Calculation of the Coil Impedance for Nondestructive Testing

本文研究了均匀半空间导体内含有任意形状三维缺陷时放置式线圈阻抗增量的数值模型，提出了一种计算阻抗增量的“半解析体积分方程法”。它包括本文首次导出的不含微分项和积分项的均匀半空间导体并矢格林函数解析式，缺陷区域的剖分方法，离散方程组的系数矩阵和右端向量的计算，非对称复系数方程组的求解以及阻抗增量计算等。用ＴＥＡＭＷｏｒｋｓｈｏｐ问题１５作为验证模型，对比结果表明，计算值和测量值吻合良好。

in this paper, an numerical model for calculating impedance increment of air-cored probe coil detecting homogeneous conducting half-space with arbitrary shape three-dimension flaws was studied. A method of volume integral equation with semi-analytic form to calculating impedance increment was presented. It includes a new dyadic Green's function formula without differential and integral terms,a technique for dividing the flaw space into elements,the calculation of left-hand side terms and right-hand side terms of discrete equations,the solution of asymmetric complex coefficient equations and calculation of impedance increment. Finally, as an example the TEAM (Testing Electromagnetic Analysis Methods) Workshop Problem No. 15 was calculated. The calculated results are is good agreement with its experimental results. With the presented analytic function formula,the calculating speed is greatly increased in comparison with other numerical methods.