Induced circumferential current for transverse crack detection on a pipe string

Abstract

Alternating current field measurement (ACFM) has been proven to be a promising technique for detecting and sizing surface cracks using an induced current. Due to the confined induced current region, the induced current cannot bypass long and narrow transverse cracks on a pipe string, which makes the conventional ACFM method insensitive to transverse cracks. In this paper, a broad full 360º circumferential current induced by a novel feed-through ACFM probe is presented for detecting transverse cracks on a pipe string effectively. The distortion of the circumferential current and characteristic signals of a transverse crack are analysed by both simulations and experiments. Our results show that the induced circumferential current is disturbed by a transverse crack on the surface of the pipe string. Characteristic signals obtained from the distorted space magnetic field associated with the disturbed circumferential current can be used to evaluate a small opening transverse crack. The results indicate that the induced circumferential current can be employed to detect small opening transverse cracks on a pipe string effectively.

A Novel ACFM Probe With Flexible Sensor Array for Pipe Cracks Inspection

“…However, the detection range of the micropencil probe is relatively small and the efficiency is relatively low. Li et al proposed a feed-through ACFM probe with sensors array for pipe string cracks inspection [24]- [26]. Feng et al presented an alternating current field measurement probe for pipeline inner inspection [27].…”

Application of induced circumferential current for cracks inspection on pipe string

“…The model consists of a mild steel pipe and an external coaxial excitation coil [11][12]. For the symmetry, half model is built by employing the Solid 117 module in ANSYS.…”