Eddy Current Sensor Array for Electromagnetic Sensing and Crack Reconstruction with High Lift-Off in Railway Tracks

Area of Science:

• Materials Science
• Non-Destructive Testing
• Railway Engineering

Background:

• Rail track integrity is crucial for safety and economic reasons.
• Eddy current (EC) testing offers a non-destructive method for defect detection.
• Distinguishing closely spaced cracks, like those from rolling contact fatigue (RCF), requires careful consideration of spatial resolution and sensor lift-off.

Purpose of the Study:

• To develop and evaluate a multi-channel eddy current sensor array for rail defect detection.
• To reconstruct rail defects using inverse algorithms based on sensor scanning data.
• To assess the system's performance in identifying cracks at various depths and spacings.

Main Methods:

• Development of a multi-channel eddy current sensor array.
• Application of inverse algorithms (direct and iterative approaches) for defect reconstruction.
• Experimental evaluation using a standard rail test piece with controlled probe lift-off (4-6 mm).

Main Results:

• The developed EC system successfully detected defects on a standard rail test piece.
• Reconstruction results clearly identified cracks at different depths and spacings.
• The multi-channel sensor array demonstrated effectiveness in rail defect characterization.

Conclusions:

• The multi-channel eddy current sensor array is a reliable and efficient tool for rail track defect detection.
• The inverse algorithm-based reconstruction effectively visualizes rail defects, including closely spaced cracks.
• This technology contributes to improved rail safety and maintenance by enabling precise defect identification.