管材远场涡流有限元仿真及内外壁缺陷检测灵敏度分析

Abstract

远场涡流作为涡流无损检测技术的一个重要分支，目前在各个行业的管道日常维护和安全保障中发挥着重要的作用。本文重点对有限元方法在远场涡流仿真中的应用进行了研究。首先通过建立有限元电磁仿真模型，对于远场涡流效应的基本现象，如“矢位峡谷”、“相位节点”等现象进行了仿真研究，并对其结果进行了分析。同时为进一步证实铁磁性管道中远场涡流相对于常规涡流技术的优势所在，选取分别位于远场区和近场区的内外壁缺陷进行有限元仿真和对比分析。Remote Field Eddy Current (RFEC) is an important branch cut of eddy current nondestructive testing (NDT) technique, and is drawing more and more attention in the testing and repairing of pipes and tubes. The finite element method used for RFEC simulation was researched in this thesis with detail. Firstly, some important phenomena of RFEC technique such as “amplitude canyon” and “phase knot” were simulated and analyzed. At the same time, to clarify the superiority of RFEC technology used for ferromagnetic tube compared with conventional eddy current, differential defects in “near field” and “remote field” were chosen to simulate and analyzed; Finally, advantages of remote field eddy current for ferromagnetic tube NDT were drawn compared with conventional eddy current.