Research on defect detection of high-speed rail based on multi-frequency excitation composite electromagnetic method

The rail under high pressure work will grow damage. In the high-speed railway, defects development initially manifests as opening diagonal defects on the surface and buried defects near surface of the rail, and the existing non-destructive testing (NDT) methods find it difficult to achieve comprehensive detection and assessment of rail surface and near surface defects. This paper proposes a multi-frequency excitation composited electromagnetic detection based on different detection characteristic of the system, which can be used to achieve comprehensive assessment of rail surface and near-surface defects. A high-speed rail experimental system is designed to implement experimental analysis which finds that the system can effectively improve the accuracy, anti interference and stability of surface defect assessment, and realize the quantitative assessment of buried defects. And the multi-frequency composited electromagnetic detection method can also suppress the attenuation of eddy current signal at high speed and improve the signal-to-noise ratio.