| Project/Area Number |
10555156
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| Research Category |
Grant-in-Aid for Scientific Research (B).
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
構造工学・地震工学
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
HIROSE Sohichi Tokyo Institute of Technology, Graduate School of Information Sci. and Eng., Professor, 大学院・情報理工学研究科, 教授 (00156712)
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| Co-Investigator(Kenkyū-buntansha) |
KIMOTO Kazushi Tokyo Institute of Technology, Graduate School of Information Sci, and Eng., Research Assistant, 大学院・情報理工学研究科, 助手 (30323827)
WADAKA Shusou Mitsubishi Electric Co., Information Tech. R & D Center (1998-1999), 情報技術総合研究所, 参事(研究職)
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| Project Period (FY) |
1998 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥5,500,000 (Direct Cost: ¥5,500,000)
Fiscal Year 2000: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1999: ¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1998: ¥2,300,000 (Direct Cost: ¥2,300,000)
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| Keywords | quantitative nondestructive evaluation / numerical simulation / ray theory / boundary element method / finite difference method / modeling of transducer / inverse problem / visualization of flaw shape / 超音波非破壊検査 / 水浸探触子 / 線形化逆解析 / シミュレーション / SH波探触子 / 水浸超音波法 / Rayleigh積分 / 超音波非破壊評価 / 円筒波 / 散乱 / 半無限弾性体 / 厚板 |
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| Research Abstract |
The aim of the present study is to develop a quantitative ultrasonic method for large complex structures. The following research topics have been investigated ; 1. Development of numerical codes for wave analysis of complex structure members, 2. Characteristic evaluation of ultrasonic transducers and incident wave fields, and 3. Application to experimental data. In the first topic, effective wave analysis methods, which combine a ray theory with a boundary element method or a finite difference method, have been developed. The ray theory is an approximation method in the high frequency range, which requires little computational effort if the scatterer has a simple geometric shape. On the other hand, numerical methods like boundary element method and finite difference method can be applied to analyze wave fields it arbitrary complex structures. In this study, the numerical methods of the boundary element method or the finite difference method were used to investigate the complex scatteri
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ng phenomena by flaws, whereas reflection and transmission on simple outer boundaries were analyzed by the ray theory. In the second topic of the evaluation of ultrasonic transducers and incident waves, the inverse problem was formulated to estimate the vibration modes on the surface of an immersion transducer from observed waveforms. The problem is a typical inverse problem, in which the solution is sought to minimize the difference between theory and measurement. The Tikhonov regularization method was adopted to obtain a stable solution. In the third topic, the numerical methods developed in the first topic were applied to various experimental configurations including step, slit, welding flaw, defects in cylindrical bar and thick plate. Comparison between experiment and numerical results showed a good agreement. The flaw shapes were, furthermore, visualized by means of SAAF and linearized inverse method. It was shown that the resolution of the imaging of flaw shapes has been improved by taking account of multiple ray paths. Less
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