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Adiabatic shear bands in high strain-rate plasticity

Tuesday, July 28, 2009 - 9:00am - 9:50am
EE/CS 3-180
Athanasios Tzavaras (University of Maryland)
We consider a system of hyperbolic-parabolic equations describing
a material instability mechanism associated to the formation of
shear bands at high strain-rate plastic deformations of metals.

We consider the case of adiabatic shearing and derive
a quantitative criterion for the onset of instability:
Using ideas from the theory of relaxation systems
we derive equations that describe the effective
behavior of the system. The effective equation turns out to be
a forward-backward parabolic equation regularized by fourth order term.

Further, we study numerically the effect of thermal diffusion on the
evolution of these bands. It turns out that while localization initially
forms at a later stage of the deformation heat diffusion has the
power hinder and even altogether suppress localization and even return
the evolution to uniform deformation.
(joint work with Th. Katsaounis and Th. Baxevanis, Univ. of Crete).
MSC Code: 
70H11