巻号一覧
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44 巻, 1 号
選択された号の論文の5件中1～5を表示しています
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論文
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高梨 正祐, 山際 謙太, 泉 聡志, 酒井 信介2006 年 44 巻 1 号 p. 3-11
発行日: 2006年
公開日: 2006/03/01
ジャーナル フリーSince evidences of fracture processes are remained on the fracture surfaces, a fractography method is usually applied to failure analysis of actual components. This method, however, contains some problems such as lack in objectivity to the analysis result, requirement for highly skilled technique, and retirement of aging skilled operators without handing down technique to next generation.
In order to solve these problems, it is considered that quantitative parameters should be introduced to fracture surface analysis. In this paper, therefore, we develop a fracture surface database system which can be easily used on the Internet to support unskilled engineers to analyze fracture surfaces. In this database system, users can search the fracture surfaces by key words like fracture modes, materials, and so on. In addition, this database system is designed so as to compute characteristic parameters of fracture surfaces such as roughness parameters and fractal dimension. The users can compare images and make decision on the fracture surface analysis based on the characteristic parameters. This system also helps document management automatically that currently relies on engineers in charge and contributes to improve data reusability.抄録全体を表示PDF形式でダウンロード (559K) -
Hiroshi KAWATE, Hanurajie BASKAN, Masaaki ISHIO, Kazuyoshi SEKINE2006 年 44 巻 1 号 p. 12-23
発行日: 2006年
公開日: 2006/03/01
ジャーナル フリーThe present study has been designed to characterize small voids, due to the Kirkendall effect, in the neighborhood of bonding interface in the Cu⁄Ni clad metals for micro-batteries. These small voids, being the source of destruction, could harm the electric resistance and the heat conductivity, both of which are important factors of the products. The method employed in this study is the ultrasonic technique with immersion type focused transducer and signal processing. We focused on the discrimination between the two adjacent pulse echoes from the bonding interface and void layer and also on identifying the void signal by means of wavelet transform analysis with Coiflet wavelet as mother one. It was experimentally confirmed that the ultrasonic method presented here has been successfully applied for evaluation of the Kirkendall voids in the Cu⁄Ni thin clad metal sheets.抄録全体を表示PDF形式でダウンロード (387K) -
吉川 正樹, 堀川 浩之, 佐々木 一彰2006 年 44 巻 1 号 p. 24-37
発行日: 2006年
公開日: 2006/03/01
ジャーナル フリーThis paper proposes a new failure assessment method for a steel pipe bend subjected to internal pressure and bending moment. The maximum bending moment of a pipe bend subjected to internal pressure is larger than that of a pipe bend subjected to only bending moment as well as previous studies. However, it was experimentally confirmed in the present study that the critical deformation (maximum bending angle) of a pipe bend subjected to internal pressure is relatively small. In addition, it was found that cracks initiate at the most deformed part of a pipe bend under the unloading process of both the internal pressure and the applied load after large deformation. Critical deformation and crack initiation position of a pipe bend were evaluated using both a new failure criterion established by the small-scale tests, and the history of stress and strain obtained from the FE-analyses. Furthermore, the failure criterion was compared with the some criteria proposed by other researchers, and the applicability of those failure assessment methods was discussed.抄録全体を表示PDF形式でダウンロード (1084K) -
弥富 政享, 富士 彰夫, 齋藤 規子, 吉田 敏明2006 年 44 巻 1 号 p. 38-46
発行日: 2006年
公開日: 2006/03/01
ジャーナル フリーFor aged power plants in Japan, the life extension beyond the original design lifetime with retaining the safety and cost-effective is needed. Therefore it is important to minimise the risk and maintenance cost to keep operating the plants until the plants become uneconomic or unsafely. Life-Cycle Maintenance (LCM) is proposed for optimising maintenance plan with reliability in the life of the plants. Risk Based Maintenance (RBM) is included in the LCM to assess the risk of components in the plants. Life Cycle Cost (LCC) and the investment assessment may be also conducted to decide the most cost effective maintenance strategy, if several maintenance strategies are proposed in RBM.
In this paper, concept and an application of the LCM are described to optimise maintenance plan in the lifetime of a plant. It was found that the LCM is quite useful method to plan the most cost effective maintenance strategies in the lifetime of the plant.抄録全体を表示PDF形式でダウンロード (481K) -
Naoya KASAI, Takao MIZOGUCHI, Kazuyoshi SEKINE2006 年 44 巻 1 号 p. 47-54
発行日: 2006年
公開日: 2006/03/01
ジャーナル フリーThe continuous magnetization is usually applied to the Magnetic Flux Leakage (MFL) testing for ferromagnetic specimens. In this case, the detectability of flaws may be strongly influenced by the stray field from magnetization equipment. This paper describes the MFL technique for surface flaws in ferromagnetic components by using the residual magnetization procedure without the stray field. The Magneto-Impedance (MI) devices having high sensitivity to magnetic fields was used as a magnetic sensor to measure residual magnetic leakage flux density distribution arising from flaws, which were considered to be very low field strength.
Firstly, the vertical components of the residual magnetic leakage flux density distribution from the parallelepiped flaws were measured by the MI sensor, and the measured results showed to be symmetric with respect to the center of parallelepiped flaws. A lot of noise was also measured because the MI sensor is sensitive. Therefore, the wavelet decomposition and reconstruction techniques were applied for the cancellation of the noise. Comparing these experimental results with ones by an ordinary Hall probe, excellent nature of this MI sensor having high sensitivity and high resolution in the proposed MFL system has been confirmed. And then, the quantitative evaluation method for surface flaws based on the MFL technique by combined use of residual magnetizing procedure and the MI sensor was presented.
Moreover, the test specimen with the butt weld and the coating was measured by the MI sensor. It was clear that flaws were detected by the cancellation of the weld signals and the signal processing.抄録全体を表示PDF形式でダウンロード (384K)
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