1991 Fiscal Year Final Research Report Summary
Estimation o inside stress distribution and destruction of metal using nonlinear dependency of sound velocity on stress
| Project/Area Number |
02402037
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| Research Category |
Grant-in-Aid for General Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Research Field |
計測・制御工学
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
SATO Takuso Tokyo Institute of Technology, The Graduate School at Nagatsuta, Department of Precision Machinery Systems, Professor, 大学院総合理工学研究科, 教授 (20016760)
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| Co-Investigator(Kenkyū-buntansha) |
SASE Mikiya Tokyo Institute of Technology, The Graduate School at Nagatsuta, Department of P, 大学院総合理工学研究科, 助手 (20225907)
KOSUGI Yukio Tokyo Institute of Technology, The Graduate School at Nagatsuta, Department of P, 大学院総合理工学研究科, 助教授 (30108237)
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| Project Period (FY) |
1990 – 1991
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| Keywords | Nondestructive / Ultrasonic Waves / Stress Perturbation / Metals Condition |
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| Research Abstract |
The objective of the research was the development of new techniques for evaluation of the condition of metals by using nonlinear dependence of ultrasound velocity on the stress. Especially the use of stress perturbation generating pumping waves and the velocity change detecting ultrasonic probing waves is key point for localization or imaging of the condition inside of metals from the detection of the interaction at the crossing region of the two waves. First, i) the nonlinear dependency of sound velocity on stress is examined by using newly obtained stress-strain system and ultrasonic wave system of 50 MHz, then ii) the nonlinear relation is formulated by using equivalent linear and 2nd and 3rd order nonlinear elastic constants and these values are derived from the experimental results. iii) The pumping system which gives about 1 Mpa stress perturbation of 5 musec duration inside metal is constructed and the probing wave of 50 MHz which can detect 0.01 degree of dynamic phase change is also constructed. iv) They are used to measure local nonlinear elastic constants of metal. v) A new characteristic value to evaluate the state of metal is introduced as a function of the nonlinear elastic constants. Finally, as an example, vi) it is applied for the evaluation of elastic deformation limiting stress value inside of metal and the usefulness for the prediction of destruction of metal is demonstrated.
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