Abstract: Rail head transverse cracks were a kind of rail damages that possessed the greatest threat to railway traffic. Therefore, simultaneously quantifying the surface and subsurface defects of the rails were of great significance. A new defect evaluation method was presented based on the transient features of PMFL detection signals, which allowed simultaneous evaluation of the depth and burial depth of surface or subsurface defects. The detection signals fluctuated on the rising edges when the excitation was large and two novel features were extracted from this phenomenon. The functional relationships among the features and the defect parameters were established, thus the measured defects could be quantitatively evaluated. Finally, three other defects were used to verify this method, and the evaluation and actual data errors of the defects depth and burial depth are all within 0.2 mm.

Key words: pulsed magnetic flux leakage(PMFL), track inspection, defect quantitative evaluation, feature extraction

摘要： 轨头核伤是对铁路行车威胁最大的一种钢轨损伤，因此同时检测出钢轨的表面和近表面埋藏缺陷对保障铁路的安全运行有着重要意义。基于从脉冲漏磁检测信号中提取的暂态特征，研究了轨道缺陷评估新方法，该方法可以同时评估表面和近表面埋藏缺陷的深度及埋藏深度。当施加激励较大时，漏磁信号在上升沿存在波动现象。从波动信号中提取两个新的信号特征，建立信号特征与缺陷参数之间的函数关系，并据此对被测缺陷进行了量化评估。使用上述方法对三个新的缺陷进行量化评估，得到的缺陷深度和埋藏深度的评估值与真实值误差均在0.2 mm以内，验证了该评估方法的可行性。

关键词: 脉冲漏磁, 轨道探伤, 缺陷量化评估, 特征提取