A novel guided wave testing method for identifying rail web cracks using optical fiber Bragg grating sensing and orthogonal matching pursuit

Ensuring safe operation of railway systems is essential. Detecting early-stage rail defects is crucial to prevent catastrophic incidents, such as derailments. Traditional manual inspection routines are often inefficient and lack robustness. This paper proposes a novel guided wave testing (GWT) method using optical fiber sensing combined with an orthogonal matching pursuit (OMP)-based data processing technique to detect rail damage by reconstructing defect-related reflective wave from complex raw signals. First, a finite element model (FEM) is constructed to simulate ultrasonic guided wave (UGW) signals and subsequent signal reconstruction using OMP demonstrates capabilities. In the experimental part, a rail segment with a vertical crack is installed with a fiber Bragg grating (FBG) sensor to receive UGW. The reconstructed signals confirm the effectiveness of our method in identifying the rail web crack location. This method offers a novel approach for rail crack identification, promoting more efficient inspection methods for extensive rail transportation networks.