2001 Fiscal Year Final Research Report Summary
Fundamental study to establish the principle of acoustoelastic residual stress measurements using off-axis waves
| Project/Area Number |
11450049
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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 | 一般 |
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| Research Field |
Materials/Mechanics of materials
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| Research Institution | Ritsumeikan University |
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Principal Investigator |
IWASHIMIZU Yukio Ritsumeikan Univ., Fac. Science and Engineering, Professor, 理工学部, 教授 (70026152)
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| Project Period (FY) |
1999 – 2000
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| Keywords | Ultrasonic Wave / Acoustoelasticity / Oblique Incidence / Longitudinal Off-axis Wave / Texture Anisotropy / Polycrystalline Model / Velocity Anisotropy / Propagation Time |
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| Research Abstract |
In most of acoustoelastic measurements so far made, the propagation direction of waves has been taken normal or parallel to specimen surfaces, and the acoustoelastic use of off-axis waves propagating obliquely against it has been hardly investigated except in few works. Tins study is concerned with the formulation of the acoustoelastic law for off-axis waves.
Theoretically, the dependence of the off-axis wave velocity on the propagation direction(θ, φ) is analyzed by the perturbation method (general approximation), and , assuming the texture anisotropy simplified based on the polycrystalline model, the result is arranged in expanded expressions (polycrystalline approximation).
In the experiment, a steel plate is taken as the specimen, and steel wedges are mainly used for transmitting and receiving off-axis waves. The propagation direction is changed by replacing wedges (wedge angle θ = 20° , 30°, 40°, 50°), and rotating the transducer direction (φ = 15° 〜 195° ), and the propagation time T(θ, φ) of off-axis reflected waves is measured in each propagation direction. From these experimental results, it is confirmed that the velocity anisotropy of longitudinal off-axis waves is explained relatively well by the general approximation. However, it is also shown difficult to explain the same velocity anisotropy quantitatively by the polycrystalline approximation.
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