著者
斎藤 隆泰 稲垣 祐生 下田 瑞斗
出版者
一般社団法人 日本非破壊検査協会
雑誌
非破壊検査 (ISSN:03675866)
巻号頁・発行日
vol.66, no.2, pp.84-89, 2017-02-01 (Released:2017-02-01)
参考文献数
14
被引用文献数
4

This paper presents an inverse scattering technique for a defect in anisotropic solids. The convolution quadrature time-domain boundary element method (CQBEM) is utilized to obtain scattered ultrasound wave data. The wave forms obtained by CQBEM are adequately treated to implement the shape reconstruction of defects in anisotropic solids. After the anisotropic elastodynamic theory is discussed, formulations for the inverse scattering technique are presented. Numerical examples for a defect in unidirectional carbon fiber-reinforced composite, austenitic steel, and isotropic steel are shown to validate the proposed methods.
著者
小倉 夏樹 佐藤 康元 北山 綱次
出版者
一般社団法人 日本非破壊検査協会
雑誌
非破壊検査 (ISSN:03675866)
巻号頁・発行日
vol.63, no.2, pp.89-95, 2014-02-01 (Released:2014-06-26)
参考文献数
15

In this paper, the performance of surface flaw detection by Magnetic Flux Testing (MFLT) using a Magneto-Impedance (MI) sensor is described. The MI sensor was used to measure the Magnetic Flux Leakage (MFL) that occurs near to flaws when the inspected material is magnetized. In order to develop a compact and handy MFL probe, a small-sized magnetic yoke was made and integrated with the MI sensor. Flat plate specimens of SS400 with artificial flaws or a fatigue crack on the surface were prepared and evaluated, first, for the relationship between artificial flaw depths and flaw signal amplitude. Secondly, the detection of the fatigue crack was attempted. The results show that the developed MFL probe can evaluate the artificial flaw depths quantitatively and detect the fatigue crack clearly. Furthermore, the developed MFL probe can measure flaws with a low excitation current, unlike a conventional MFLT. Accordingly, it is expected that a portable non-destructive inspection system with the developed MFL probe will be developed in the future.
著者
嘉村 直哉 宮崎 利行 佐々木 敏彦
出版者
一般社団法人 日本非破壊検査協会
雑誌
非破壊検査 (ISSN:03675866)
巻号頁・発行日
vol.66, no.10, pp.492-497, 2017-10-01 (Released:2017-12-20)
参考文献数
20

In this study, X-ray stress measurement of aluminum alloy A2017 using the Fourier analysis proposed by Miyazaki et al. was carried out. The validity of measured stresses was verified by a four point bending test. Coarsening grains existed in the specimen and spotty diffraction rings were obtained, nevertheless the Fourier analysis is applicable for such material. The stresses measured by Fourier analysis were in good agreement with both mechanical ones and the value obtained by the cosα method. For the single X-ray incident, the measured stress obtained from the 311 diffraction plane particularly showed such correspondence to applied stress as compared with the 222 diffraction plane. The reliability of stress measurement was improved by using the in-plane averaging, and it was effective for every diffraction plane. The effect of enlargement of the X-ray irradiation area saturates, thus the areas to average should be selected appropriately in order to measure the stresses efficiently.
著者
石井 優 草なぎ 祐紀 大谷 俊博 仲庭 正義
出版者
The Japanese Society for Non-Destructive Inspection
雑誌
非破壊検査 (ISSN:03675866)
巻号頁・発行日
vol.64, no.4, pp.179-183, 2015

In this study, we apply non-contacting nonlinear resonant ultrasound spectroscopy (NNRUS) to the evaluation of fatigue damage in pure copper. NNRUS is a combination of a contactless transducer, electromagnetic acoustic transducer (EMAT), and nonlinear resonant ultrasound spectroscopy (NRUS). The NRUS technique is exploits the significant nonlinear behavior of damaged materials. The resonant frequency of an object is studied as a function of its excitation level. As the excitation level increases, the elastic nonlinearity is manifested by a shift in the resonance frequency. The change in nonlinearity rapidly increases from 80% of fatigue life and is synchronized with the change in the attenuation coefficient with fatigue progression. This novel phenomenon is interpreted in terms of change in dislocation mobility and the dislocation rearrangement. TEM (Transmission Electron Microscope) observations supported this view. This technique has the potential to assess the level of damage and to predict the fatigue life of metals.