ABSTRACT

A metal clad plate consists of a base layer and a clad layer of different materials. When testing clad plate using the eddy current (EC) method, the variation of EC density along the thickness direction in clad plate is complicated owing to the interface between the layers. This article attempts to investigate the characteristics of the variation of EC density in the thickness direction in clad plate based on finite element analysis. The results are then used for revealing the mechanism of the relation between coil voltage and the thickness of the clad layer which is essential for the measurement of cladding thickness. Thereupon, the experiment of measuring cladding thickness is performed, in which the testing frequency is selected based on the voltage-thickness relation. It turns out that the measurement is accurate and the results have good linearity.

摘要

金属复合板由不同材料的基层和复合层组成。当使用涡流（EC）方法测试复合板时，由于层间的界面，复合板中EC密度沿厚度方向的变化很复杂。本文尝试基于有限元分析研究复合板厚度方向EC密度变化的特征。然后将结果用于揭示线圈电压与包层厚度之间关系的机制，这对于包层厚度的测量是必不可少的。于是，进行了包层厚度测量实验，根据电压-厚度关系选择测试频率。