1999 Fiscal Year Final Research Report Summary
Development and Application of the Unsteady Wave Sensing System by Using Embedded Gauges
| Project/Area Number |
09650115
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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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 | Tohoku Gakuin University |
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Principal Investigator |
SATO Yasuhisa Faculty of Engineering, Tohoku Gakuin University, Professor, 工学部, 教授 (50005419)
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| Co-Investigator(Kenkyū-buntansha) |
KONO Yukio Faculty of Engineering, Tohoku Gakuin University, Professor, 工学部, 教授 (30137583)
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| Project Period (FY) |
1997 – 1999
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| Keywords | Material testing / PVDF gauge / Unsteady wave / PMMA / Polycarbonate / Aluminium / Hugoniot Curve / Plate-impact experiment |
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| Research Abstract |
Plate-impact experiments are conducted under the loading-reloading-unloading stress condition using a powder gun facility. We have developed the unsteady-wave-sensing-system (UWSS) to evaluate the unsteady wave propagation characteristics of the materials in the uniaxial strain state. The procedures are as follows.
First, stress as a function of time at three locations in the specimen is measured by using polyvinylidene fluoride (PVDF) gauges. From these measurements, values of the phase velocities U ィイD1σィエD1associated with the stress profile of the wave can be obtained at two locations, which are respectively, in the middle of each pair of neighboring gauge locations. Second, particle-velocity profiles at these two locations can be computed from the conservation relation of momentum. Therefore, values of the other wave velocity UィイD1σィエD1 associated with the particle-velocity profiles can be found. Finally, the strain can then be obtained from integration of the conservation relation for mass.
Results obtained in the region of our experimental stress for polymethyl methacrylate (PMMA) or polycarbonate (PC) or aluminium (JIS:A1lOO) are as follows.
(1) Both the propagation velocities of stress and particle-velocity are sometimes different.
(2) Regarding the stress-strain diagram, a point of transition from loading to reloading is almost on the Hugoniot curve, while a point of transition from reloading to unloading is above the Hugoniot curve.
(3) The Hugoniot curve must be thought to be distinguished from characteristics including loading-history such as loading-reloading.
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