铁磁性构件缺陷的脉冲涡流检测传感机理研究

铁磁性构件的脉冲涡流检测法是一种融合了漏磁检测与涡流检测的新的复合磁传感检测法。建立了脉冲涡流复合传感有限元仿真模型,仿真分析了铁磁性构件电导率、磁导率和导入直流电流激励大小对脉冲涡流响应信号的影响规律。实验结果表明:随着导入直流电流激励增加,铁磁性构件表面缺陷漏磁场和电流密度引起扰动磁场的复合场对脉冲涡流响应信号的影响更显著,而铁磁构件亚表面埋藏缺陷随着缺陷深度的增大而增大,缺陷漏磁及电流扰动磁场的复合场对脉冲涡流响应信号的影响变小,涡流响应信号占主导地位,为脉冲涡流传感器设计奠定理论基础。

Research on sensing mechanism of ferromagnetic component flaw using pulsed eddy current testing

Pulsed eddy current testing is a new combined magnetic sensing detection method for the nondestructive testing of ferromagnetic materials, which integrates magnetic flux leakage testing and eddy current testing. The finite element simulation model of pulsed eddy current combined sensing testing is built for ferromagnetic materials. The influence of the conductivity and permeability of the ferromagnetic material, and the amplitude of the direct excitation current for the ferromagnetic samples on the pulsed eddy current response signal is analyzed in simulation. The experiment results show that as the import direct current excitation increases, the influence of the combined field of the surface defect leakage magnetic flux and the perturbed magnetic field on the pulsed eddy current response signal is getting more obvious. However, as the defect depth of the ferromagnetic sample increases, the influence of the combined field of the surface defect leakage magnetic flux and the perturbed magnetic field on the pulsed eddy current response signal is getting less significant. The eddy current takes the dominate position in this situation. The study results lays a theoretical foundation for the design of pulsed eddy current sensor.