Effect of scanning acceleration on the leakage signal in magnetic flux leakage type of non-destructive testing

TL;DR

This study examines how the acceleration of the inspection system affects the leakage signals in magnetic flux leakage non-destructive testing, revealing a significant decrease in signal strength due to magnetic field distortion caused by eddy currents.

Contribution

It provides experimental and simulation insights into the impact of system acceleration on leakage signals, aiding optimization of MFL inspection accuracy during machine movement.

Findings

Leakage signal decreases by 20-30% under acceleration

Magnetic field distortion due to eddy currents causes signal reduction

Measurement at constant velocity is recommended for accuracy

Abstract

This novel work investigates the influence of the inspection system acceleration on the leakage signal in magnetic flux leakage type of non-destructive testing. The research is addressed both through designed experiments and simulations. The results showed that the leakage signal, represented by using peak to peak value, decreases between 20% and 30% under acceleration. The simulation results indicated that the main reason for the decrease is due to the difference in the distortion of the magnetic field for cases with and without acceleration, which is the result of the different eddy current distributions in the specimen. The findings will help to allow the optimisation of the MFL system to ensure the main defect features can be measured accurately during the machine acceleration. It also shows the importance of conducting measurements at constant velocity, wherever possible.