Development and Application of Wide Bandwidth Magneto-Resistive Sensor Based Eddy Current Probe

Abstract

ABSTRACT. The integration of magneto-resistive sensors into eddy current probes can significantly expand the capabilities of conventional eddy current nondestructive evaluation techniques. The room temperature solid-state sensors have typical bandwidths in the megahertz range and resolutions of tens of microgauss. The low frequency sensitivity of magneto-resistive sensors has been capitalized upon in previous research to fabricate very low frequency eddy current sensors for deep flaw detection in multilayer conductors. In this work a modified probe design is presented to expand the capabilities of the device. The new probe design incorporates a dual induction source enabling operation from low frequency deep flaw detection to high frequency high resolution near surface material characterization. Applications of the probe for the detection of localized near surface conductivity anomalies are presented. Finite element modeling of the probe is shown to be in good agreement with experimental measurements.

A Review on Non-destructive Evaluation of Civil Structures Using Magnetic Sensors

“…Wincheski and Simpson [28] integrated MR sensors with EC probes. They designed a new EC probe incorporating a dual induction source that can be operated for deep flaw detection with low-frequency EC, and near-surface material characterizations with high resolution with high frequency EC.…”

Improved Magnetic Tunnel Junctions Design for the Detection of Superficial Defects by Eddy Currents Testing

“…Another advantage of MR sensors rely on their high-spatial resolution (down to nanometer scale) when compared with inductive sensors (down to 1 mm). This advantage has been recently used for the detecion of very small surface defects with anisotropic MR (AMR) [4], [5] and giant MR (GMR) [6], [7] sensors. This non-destructive testing (NDT) method relies on the induction of electrical currents on metallic blocks, which may be distorted in the presence of defects or other features in the block.…”