Influence of specimen velocity on the leakage signal in magnetic flux leakage type nondestructive testing

TL;DR

This study examines how specimen velocity affects magnetic flux leakage signals in nondestructive testing, revealing velocity-induced asymmetries and optimal sensor placement considerations through numerical simulations.

Contribution

It provides new insights into the impact of specimen velocity on magnetic flux leakage signals and discusses sensor placement strategies based on velocity effects.

Findings

Magnetic field symmetry breaks with increased velocity.

Peak magnetic induction shifts along the specimen movement direction.

Sensor location influences the velocity dependence of the axial magnetic signal.

Abstract

We investigate the influence of the specimen velocity on the magnetic flux leakage with the aim of selecting the optimum sensor locations. Parametric numerical simulations where the specimen velocity was in the range [0.1-20] m$\cdot$s$^{-1}$ were carried out. As the specimen velocity is increased, the magnetic field varies from being symmetrical to being asymmetric. For the radial magnetic induction, the peak to peak value moves from the centre of the bridge towards the direction of the specimen movement. For the axial magnetic induction, the specimen velocity influence is dependent on the sensor location and a signal-velocity independent region was discussed.