脉冲调制涡流检测金属构件亚表面腐蚀缺陷研究

Research on pulsed-modulation-based eddy current evaluation of subsurface corrosion in defect metallic structures

亚表面腐蚀缺陷严重影响在役装备关键金属构件的完整性。本文提出一种新型脉冲涡流检测技术,即脉冲调制涡流检测技术,探究该技术在金属构件亚表面腐蚀缺陷检测和评估中的技术优势。首先,基于退化磁矢位法,建立了脉冲调制涡流检测金属构件亚表面腐蚀缺陷的高效有限元仿真模型,仿真分析了脉冲调制涡流检测信号及其特征与金属构件亚表面腐蚀缺陷深度间的关联规律,探究了该技术的优势性。同时,搭建了脉冲调制涡流/脉冲涡流双检测试验系统,通过试验,进一步探究两种技术在金属构件亚表面腐蚀缺陷检测中的优劣,试验结果验证了仿真分析结论。研究表明,对于金属构件亚表面腐蚀缺陷检测,脉冲调制涡流检测技术较脉冲涡流检测技术,具有更高的灵敏度。

Subsurface corrosion defect severely influences the integrity of crucial components of in-service apparatus.In light of this,this paper proposes a new pulsed eddy current technique （PEC）,namely pulsed-modulation-based eddy current technique （PMEC）,and intensively inves-tigates its advantages regarding inspection and evaluation of subsurface corrosion defect in metal-lic structures.The correlations of PMEC signals and their features with subsurface corrosion in different depths are firstly analyzed via the finite element analysis based on the numerical PMEC model established using reduced magnetic vector potential method.The advantages of PMEC over PEC are identified via simulations.In parallel,an experimental system implementing PMEC as well as PEC is built up.Through experiments,PMEC and PEC are further compared regarding inspection of subsurface corrosion defect in conductors.The experimental results are found to be in agreement with those from simulations.The results from both simulations and experiments in-dicate that compared with PEC,PMEC has higher sensitivity to subsurface corrosion defect in metallic structures.