| Budget Amount *help |
¥4,700,000 (Direct Cost: ¥4,700,000)
Fiscal Year 2000: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1999: ¥4,200,000 (Direct Cost: ¥4,200,000)
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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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