脉冲电磁缺陷检测融合机理研究

针对铁磁性构件表面和下表面缺陷检测的难题,建立了脉冲电磁检测模型,揭示了表面缺陷和下表面缺陷的脉冲漏磁与脉冲磁阻检测相融合的物理机制。仿真与实验结果表明:铁磁性构件表面缺陷存在漏磁,而下表面缺陷主要体现在脉冲磁阻的变化。对于不同深度的铁磁性构件表面缺陷,GMR传感器拾取的脉冲漏磁响应信号的检测结果线性度更好,灵敏度更高;对于不同深度的铁磁性构件下表面缺陷,双侧检测线圈拾取的脉冲磁阻响应特征值与缺陷深度的变化关系呈近似线性增长关系,区分度较大,检测性能更好。

Research on the Fusion Mechanism of Pulsed Electromagnetic for Defect Detection

Aimed at the problem that the defects of surface and subsurface are very hard to detect on the ferromagnetic components, the pulsed electromagnetic testing model is established. The physical mechanism of a method composed of the pulsed magnetic flux leakage (PMFL) and pulsed magnetic reluctance (PMR) under the surface and subsurface defect is revealed. Both the simulation and experimental results indicate that the magnetic flux leakage exists in the surface defect of ferromagnetic, but the subsurface defect detecting signal is the change of the pulsed magnetic resistance. For the different depth of the surface defects, the pulse leakage magnetic response signal picked by GMR sensor is better linearity and higher sensitivity; For the different subsurface defects of ferromagnetic components, the relationship between the characteristic value of the pulse magneto resistance response and the depth of the defects is similar to the linear growth relationship, and the discrimination degree is larger and the detection performance is better.