Electric transverse currents detecting sensor based on strong magnetic resistance and method thereof

Abstract

The present invention discloses an eddy current detecting sensor and a detecting method based three giant magneto-resistances. An excitation coil is adopted to generate an alternating magnetic field and arranged above a detected object. A giant magneto-resistance I, a giant magneto-resistance II and a giant magneto-resistance III with pair-wise orthogonal magnetic sensitivity directions between the excitation coil and the detected object. Wherein, the giant magneto-resistance I is connected with an amplifying circuit I. The giant magneto-resistance II is connected with an amplifying circuit II. The giant magneto-resistance III is connected with an amplifying circuit III. The amplifying circuit I, the amplifying circuit II and the amplifying circuit III output voltage signals corresponding to the giant magneto-resistance I, giant magneto-resistance II and giant magneto-resistance III. The voltage signal comprises eddy current distribution information of the detected object. The eddy current detecting sensor based on three giant magneto-resistances can not only bring high sensitivity and spatial resolution to deep or multilayer flaw detection but also benefit quantitative defect analysis.

Description

technical field [0001] The invention relates to an eddy current detection sensor based on three giant magnetoresistances and a detection method thereof. Background technique [0002] The basic principle of eddy current testing is: when the excitation coil carrying alternating current is close to the conductive object to be tested, according to Faraday's law of electromagnetic induction, a current will be generated in the conductive object to be tested, that is, eddy current. The size, phase and flow form of the eddy current will be affected by factors such as the conductivity and shape of the object to be inspected, and the electromagnetic field generated by the eddy current contains information such as the size and phase of the eddy current. Therefore, it is possible to analyze properties such as the thickness and electrical conductivity of the inspected object and the presence or absence of defects in the inspected object by detecting the magnetic field. [0003] Since th...

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Problems solved by technology

[0005] Another disadvantage of traditional eddy current inspection devices based on a single sensor is that it is difficult to quantify the detected defects, especially when targeting deep or multi-layer defects

Due to the integral effect and the single magnetic field direction, the obtained detection data contains less information, it is difficult to obtain the corresponding relationship between the size of the defect and the size of the detection signal, and it also takes more time to calculate the detection results

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