涡流检测缺陷定量评估的研究

在涡流检测中实现缺陷定量评估具有重要意义。通常涡流检测是利用线圈阻抗变化来实现缺陷检测,分析受缺陷扰动的磁场量B的分布变化,比传统的涡流检测方法更有利于实现缺陷定量评估。利用有限元方法,对有裂纹的金属平板的空间磁场进行了数值仿真。仿真结果证实可通过分析磁场量B的变化来实现缺陷定量评估,并得到了缺陷的长度、深度与平板表面的磁场分量之间的量值关系。对平板裂纹的定量评估提供了理论上的依据。

RESEARCH ON QUANTITATIVE EVALUATION OF DEFECT WITH EDDY CURRENT TESTING

Quantitative evaluation of defect in metallic structures and components was very important in eddy current testing. The variation of coil impedance was used to detect the defect in conventional eddy current testing. However, the size of defect was identified more quantitatively and accurately if the distributing characteristic of the electromagnetic field perturbed by defect were used. The numerical simulation analysis of the magnetic field around surface-breaking defect in metallic plate was accomplished by means of finite element method (FEM). The simulation results showed clearly the feasibility and validity of realizing the quantitative evaluation of defect based on interpretation of the magnetic field B, and the relation between the perturbed field component and size of surface defect was achieved. Conclusions above could be used as a theoretical argument for quantitative evaluation of defect in plate.