Electromagnetic acoustic resonance (EMAR) method is useful for measuring thickness of pipe. But in the case of thickness changing complicatedly in part of pipe wall thinning for various factor, accurate thickness measurement is difficult. In this study, thickness of specimens of pipe corroded under various conditions is evaluated by EMAR. The error of thickness evaluation is investigated in view of maximum value of spectrum and roughness and curvature of pipe. As a result, it is suggested that signal streng...
英字タイトル:
Evaluation of pipe wall thinning with electromagnetic acoustic resonance method considering effects of roughness and curvature of inner surface.

In the previous study, we proposed an eddy current magnetic signature method as a way to evaluate the residual strain of low carbon steels. However, the dependence of the pearlite content which affects magnetic properties of steel on the eddy current magnetic signature has not been discussed yet. In this study, to evaluate the effect of the pearlite content on the eddy current magnetic signature, two kinds of low carbon steels with different pearlite contents are investigated. The specimens with different r...
英字タイトル:
Evaluation of residual strain of low carbon steels with various pearlite contents by eddy current magnetic signature method

In this study, we focus on the eddy current testing (ECT) as a method to investigate the hydrogen embrittlement mechanism of austenitic stainless steels which are widely used in hydrogen components. ECT is applied to hydrogen-charged austenitic stainless steel AISI 304 specimens with different amounts of residual strain. Permeability values of the specimens are estimated by comparing the signals obtained by the ECT experiment and the results of the electromagnetic field analysis, and the phase transformatio...
英字タイトル:
Evaluation of Phase Transition of Austenitic Stainless Steel due in Hydrogen Embrittlement by Eddy Current Magnetic Signature Method

Eddy Current Testing (ECT) is widely used for non-destructive testing in the industrial fields. Furthermore, ECT is expected to be used not only for evaluating the integrity of products, but also in the field of fundamental research, such as the mechanism study of hydrogen assisted fatigue crack growth since ECT can evaluate electromagnetic properties. However, the low spatial resolution of ECT is an issue for such applications. To improve the resolution of ECT system, a magneto-optic (MO) element is applie...
英字タイトル:
Development and Evaluation of Eddy Current Probe Using Magneto-Optical Effect

This paper proposed the evaluation of rebar corrosion in reinforced concrete by an electromagnetic pulse-induced acoustic testing method. A strong pulsed electromagnetic force is applied to the specimen, and the rebars will generate the elastic waves. The difference in the bonding force between the rebars and concrete depending on rust is evaluated based on the intensity and waveform variation of elastic waves. In this study, the rusted and un- rusted rebar specimens are prepared, and the AE sensor is place...
英字タイトル:
Evaluation of Rebar Corrosion in Reinforced Concrete using Electromagnetic Pulse-induced Acoustic Testing Method

Electromagnetic acoustic resonance (EMAR) method is used for online evaluation of pipe-wall-thinning. In this study, the thickness of the specimens corroded under various conditions is evaluated by EMAR. The thickness is estimated applying the superposition of n th compression (SNC) method to the signals obtained from EMAR. The error of thickness evaluation is investigated in view of thinning shape and the roughness caused by corrosion. As a result, it is suggested that the shape on the order of mm does not...
英字タイトル:
Study of evaluation accuracy of pipe-wall-thinning using electromagnetic acoustic resonance