Papers by Keyword: Cosα Method

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Authors: Toshihiko Sasaki, Yohei Miyazawa, Shunichi Takahashi, Ryohei Matsuyama, Katsunari Sasaki, Koichi Hiratsuka
Abstract: The X-ray stress measurement with synchrotron radiation (SR) and an image plate (IP) was conducted using the facility of the Photon Factory (PF) of the High Energy Accelerator Research Organization (KEK). The influence of 2θ on stress measurement with the cosα method was investigated. The experiments were conducted under the conditions of 2θ=170 deg, 156.4 deg and 127 deg respectively. It was found that the hypothesis on the relation between the accuracy and the diffraction angle in the X-ray method is not valid in case of the cosα method.
Authors: Toshihiko Sasaki
Abstract: In order to study the method of the neutron stress measurement using the cosα method, a numerical simulation study was performed and the result was compared with author's former experiment. The results of the simulation study agreed with those obtained in the previous experiment, which suggests the validity of the present method for neutron stress measurement.
Authors: Toshihiko Sasaki, Shunichi Takahashi, Yuichi Kobayashi, Yukio Morii, Naoto Metoki
Abstract: The influence of the peak determination method on the area detector type neutron stress measurement method was investigated. Two peak determination methods, the half value breadth method and the centroid method, were compared and discussed in this paper. Experiments and simulation studies were carried out respectively. The first experiment was conducted during the tensile stress test with a steel specimen having the thickness of 6mm, and the second experiment was conducted with steel specimens in the stress free state having the thickness between 1 mm to 20 mm. As a result of the experiments, it was found that the peak determination method has an affect on the area detector type neutron stress measurement. A numerical simulation study was also conducted and showed similar result as the experiments.
Authors: Toshihiko Sasaki
Abstract: Measuring theory of two types of X-ray stress analysis method was compared with each other. One is the conventional method, in which zero-or one-dimensional detector is used for obtaining diffracted beam and stress is determined using the standard sin2ψ method. Another is the new type of X-ray stress analysis method, in which two-dimensional detector is used to obtain whole Debye ring and stress is determined using the cosα method. An experiment was conducted to investigate the validity.
Authors: Toshihiko Sasaki, Shunichi Takahashi, Kengo Iwfuchi, Yukio Satoh, Yoshikazu Kanematsu, Masanobu Chiba, Shigeki Takago
Abstract: In this study, a new portable X-ray stress analyzer was designed and manufactured. The purpose of its use is to evaluate the rolling contact fatigue damage in rails for establishing an effective rail maintenance method. An image plate was used in this analyzer for detecting diffracted X-ray beams. The cosα method was adopted for X-ray stress analysis from X-ray diffraction data. A fundamental experiment was made first for examning the present measurement system. Residual stresses in rails used in service for six years were also investigated in this study.
Authors: Toshihiko Sasaki, Toshiyuki Miyazaki, Hamiru Ito, Takashi Furukawa, Tsuyoshi Mihara
Abstract: Nickel based alloys are widely used in steam generator tubes for nuclear power plants. 1-D X-ray stress measurements have been used for these alloys. But 1-D method requires large equipment and it is practically impossible to measure stress in power plants. In order to overcome this problem, we adopted 2-D X-ray method which requires significantly smaller equipment. In this paper we report preliminary results of 2-D X-ray stress measurements of nickel based alloys.
Authors: Toshihiko Sasaki, Kei Koda, Yohei Fujimoto, Shoichi Ejiri, Tamaki Suzuki, Yuichi Kobayashi
Abstract: This paper shows X-ray residual stress analysis of stainless steel using 2-dimensional detection method. The 2-dimensional detection method of X-ray stress measurement will determine stress by conducting a 2-dimensional detecting of a Debye ring and analyzing the image data. The basic of typical austenitic stainless steel (JIS SUS304) was studied in this study, considering the fact that, at certain power plants, maintenance takes place to prevent stress corrosion cracking by adding compressive residual stress to the structure..
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