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Registro 1 de 2, Base de información Bciucla |
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Información de existencia
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Palabras Claves:
CHANGE OF TYPE,
HYPERBOLIC-PARABOLIC,
PHASE TRANSITION |
Resumen
RESUMEN
RESUMEN
Classical heat
pulse experiments have shown heat to propagate in waves through
crystalline materials at temperatures close to absolute zero. With increasing
temperature, these waves slow down and finally disappear, to be
replaced by diffusive heat propagation. Several features surrounding this phenomenon
are examined in this work. The model used switches between an
internal parameter (or extended thermodynamics)
description and a classical (linear or nonlinear) Fourier law
setting. This leads to a hyperbolic-parabolic change of type, which
allows wavelike features to appear beneath the transition
temperature and diffusion above. We examine the region around and
immediately below the transition temperature, where dissipative
effects are insignificant.
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Registro 2 de 2, Base de información Bciucla |
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Información de existencia
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Palabras Claves:
ADIABATIC SHEAR,
BIFURCATION,
CHANGE OF TYPE,
MATERIAL INSTABILITY,
SIMILARITY PARAMETER,
TURNING POINT,
VISCOPLASTICITY |
Resumen
RESUMEN
The linear stability of perturbed
simple shear in a ductile plastic material which can strain-soften is analyzed
on a finite time interval. An asymptotic study is made of the influence of two
small dimensionless coefficients, which are shown to be connected by a
similarity parameter. The first coefficient is a dimensionless group of
parameters which can be interpreted as the ratio of the momentum flux to the
plastic flow stress, while the second coefficient gives the scale of the
viscous damping. A criterion is derived for the minimum strain rate where the
early-time behavior changes from oscillatory to exponential.
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