GMR-Based ECT Instrument for Detection and Characterization of Crack on a Planar Specimen: A Hand-Held Solution

This paper proposes a novel instrument for eddy-current (EC) nondestructive testing on conductive materials. The instrument is composed by a smart EC probe, based on a GMR sensor, and a suitable processing unit. The key features of the proposed instrument are the capability of detecting, locating, and characterizing thin defects as superficial and subsuperficial cracks. The main goal of the proposal is the realization of a very low cost instrument that is able to reach performance comparable with instrumentation available on the market and especially suited for application fields such as aerospace and maritime. In this paper, the steps followed for the instrument realization, together with its experimental characterization, are described in detail.