The authors have already proposed microwave nondestructive testing (NDT) method on detecting both location and degree of a pipe wall thinning (PWT) inside a metal pipe. However, problems caused by iofouling inside metal pipes are also frequ ently reported in recent years. As the existence of biofilm inside a aveguide will change its wave impedance and also cause microwave reflections, the characteristic signals of iofilm defects are studied here to distinguish the biofilm and PWT defects. A pair of coaxial...
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Application of Microwaves on Remote and Nondestructive Testing of both Biofouling and Wall Thinning inside a Metal Pipe

宮 健三 Kenzo MIYA This study proposes an investment for the evaluation of tube wastage by eddy current testing. EC T signals of differential and absolute type bobbin probes are presented by numerical simulation method. The relationships between percentage of wastage and ECT signals (amplitude and phase) ar e shown. Noise from ECT is considered and the percentage of wastage is estimated from safe side....
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Evaluation of Tube Wastage by Eddy Current Testing

This study evaluates the key factors impacting on multi-mode conversion of microwave when applying microwave NDT to bent pipe inspection. Mathematical derivation demonstrates the dependence of multi- mode conversion due to a bend on three factors: the ratio of bending radius to pipe’s diameter, the bend angle and the frequency normalized with the cut-off frequency of an arbitrary mode. To verify the deducting results, numerical simulations were conducted to evaluate multi-mode conversion of bent pipe adopti...
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Evaluation of general applicability of microwave NDT to pipes with a bend focusing on mode conversion

The present study discusses electromagnetic characteristics of modeling thermal fatigue crack in numerical simulation from view point of eddy current testing. Two thermal fatigue cracks introduced into SUS304 stainless steel plates are investigated. Eddy current signals are gathered by a differential plus point probe with several frequencies, 50 kHz, 100 kHz and 400 kHz. In the numerical simulation thermal fatigue crack is modeled as a region with constant width, true profile revealed by results of destruc...
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Investigation on electromagnetic characteristics numerical simulation by eddy current testing

This study proposes to use extreme value analysis to characterize the uncertainty in estimating the wall thickness of carbon steel pipes by ultrasonic testing. The goodness of fit has been examined using experimental data measured from plate samples processed by corrosion test. A model is subsequently developed for predicting the failure probability of carbon steel pipes suffering wall thinning based on Bayesian theorem. In this model, the wall thinning rate predicted by KWU-KR model can be updated by offer...
英字タイトル:
Reliability analysis of pipes suffering wall thinning based on extreme value analysis of ultrasonic thickness measurement

吉田 光宏 Mitsuhiro YOSHIDA 山本 昌志 Masashi YAMAMOTO 中村 直樹 Naoki NAKAMURA ...
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Portable 950keV X-band Linac X-ray Source for On-site NDT

new electromagnetic method for the nondestructive evaluation of electric pumps with ball bearings is roposed. A permanent magnet generates a static magnetic field and a coil of several hundred turns wrapped round it is used to pick up eddy currents induced inside rotating ball bearings and impellers. First, a method hat make use of the autocorrelation is applied to the signals of the ball bearings. A relation between therocessed signals and the size of the defects in the bearings is obtained. In a second...
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Electromagnetic Nondestructive Detection for Wounded Bearings and Impellers andCorrelation of Size of Defect and Signal

This paper reports the optimization of a new microwave probe for the nondestructive testing of an inner wall surface of the pipe, which is one of a novel long-range inspection. The method propagates a microwave inside a pipe to detect defects appearing the inner surface on the basis of the reflection of the microwave due to the defects. In order to propagate microwave into a pipe efficiently, the optimization based on the reflection and transmission characteristics at the probe obtained by the two-dime...
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Structure Optimization of the Excitation Probe in Crack Rader Using Microwave

This study evaluates the applicability of a nondestructive testing method using microwaves to the long-range inspection of a pipe with a bend. Experimental verifications were performed using four 1 m pipes, with an inner diameter of 23 mm, connected with flanges and a 90-degree bend. The experimental verifications confirmed clear reflections due to artificial wall thinning, simulated by a short pipe with an inner diameter larger than 23 mm, even when the wall thinning was situated directly below the ben...

This paper introduces the recent progress in the development of a microwave nondestructive testing method, aiming at the rapid and long-range inspection of a pipe, in the authors’ group. ...
英字タイトル:
Development of a nondestructive testing method using microwaves to the rapid inspection of pipes