Berlin 2008 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

CPP: Fachverband Chemische Physik und Polymerphysik

CPP 7: POSTERS Rheology

CPP 7.16: Poster

Montag, 25. Februar 2008, 16:45–19:00, Poster A

Kinetic toy model for crystal plasticity — •Markus Hütter¹, Miroslav Grmela², and Hans Christian Öttinger¹ — ¹ETH Zürich, Department of Materials, Polymer Physics, CH-8093 Zürich, Switzerland — ²Ecole Polytechnique de Montréal, Montréal, Quebec, Canada H3C 3A7

We propose a kinetic toy model to describe the dynamics of sliding layers as it occurs in the plastic deformation of single crystals, be it of polymeric, colloidal, or metallic nature. As its basic ingredient, the distribution function of relative strains between adjacent crystal layers is introduced with time evolution described by a diffusion equation with periodic boundary conditions. The model highlights the conceptual difference in the dynamics of the elastic and plastic strains, the latter being related to an average hopping rate that captures the evolving reference state. We illustrate the model by calculation of the stress response for both stationary and transient conditions. In order to discuss the physics behind the parameter that drives the plastic flow in the kinetic model, we use nonequilibrium thermodynamics to unify this model with a nonisothermal hydrodynamic description, which renders the set of evolution equations closed. Finally, we examine the relation of the kinetic toy model to macroscopic theories of elasto-viscoplasticity that employ the macroscopic deformation gradient as a fundamental variable.