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Home  >  Journal list  >  Journal of the Society of Materials Science, Japan  >  Vol.55  No.3 (2006)  >  pp.276-283

Journal of the Society of Materials Science, Japan
<<Previous article Vol.55  No.3 (2006)   pp.276 - 283 Next article>>

Strain-Rate Dependence on Stress-Strain Characteristic of the Shock Wavefront in Two Kinds of Glassy Polymers

Yasuhisa SATO1), Taku UENO1), Keiou NISHIMURA2), Kazunari SUZUKI1) and Yuhichi OGAWA1)
1) Dept. of Mech. Eng., Tohoku Gakuin Univ.
2) Dept. of Metal., Graduate School of Eng., Tohoku Univ.


For numerical design of safety compartments in a cabin of aircraft to maintain a survivable environment for passengers in a crash, very-high-strain-rate mechanical-properties of many kinds of aerospace materials are indispensable. On the basis of the Unsteady Wave Sensing System (UWSS), which is composed of a plate impact experiment using three in-material gauges and nanosecond Lagrangian analyses, various variables are determined at the sensing part of the central gauge. Three stress-time histories are measured by three PVDFgauges, respectively, and the time histories of the phase velocity associated with the stress : Uσ, particle velocity : v, the phase velocity associated with the particle velocity : Uv, and strain : ε induced by impact at velocities ca. 600m/s are calculated by using those three stress-time curves and the conservation relations of mass and momentum. Then, the stress-strain curves at very high strain-rate of the order 106 to 107s−1 are derived under conditions of uniaxial strain. On the other hand, stress-stain curves at medium strain rate (ca. 102s−1) and at low strain rate (ca. 10−4s−1) under conditions of uniaxial stress were already determined by a drop-weight testing system and Instron testing machine, respectively. It is clearly shown that the stress-strain curves for PMMA and polycarbonate (PC) are both very sensitive to strain rate in the very wide range of strain-rate of 10−4s−1 to 107s−1 under conditions of uniaxial strain. As a result, power law relations between stress and strain-rate were observed with these glassy polymers under uniaxial strain conditions in the very wide strain-rate range.


Keyword:
Shock-high-pressure, Aircraft crash, Shock wavefront, Nanosecond analyses, Plate impact experiment, PVDF gauge, Glassy polymer

Received: June 17, 2005
Published online: April 26, 2006
Copyright (c) 2006 by The Society of Materials Science, Japan

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