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BP: Fachverband Biologische Physik
BP 16: Poster - Glasses / Stat. Phys. Bio. / Networks (joint DY/BP/CPP/SOE)
BP 16.4: Poster
Tuesday, April 1, 2014, 09:30–12:30, P1
Continuum Mechanics Simulations of Nonlinear Deformation of Viscoplastic Solids — •Heliana Cardenas1 and Thomas Voigtmann1,2 — 1Institut für Materialphysik im Weltraum, Deutsches Zentrum für Luft- und Raumfahrt (DLR), Köln, Germany — 2Zukunftskolleg und Fachbereich Physik, Universität Konstanz, Konstanz, Germany
When amorphous solids are formed by solidification of dense liquids slow intrinsic relaxation plays a determining role on describing their behavior. Systems like this can be perturbed by external mechanical fields driving it to a non-equilibrium regime following then non-linear deformation laws. The mode-coupling theory of the glass transition (MCT) has been extended to describe the interplay between strong external forces and slow relaxation.
A non-linear extension of the Maxwell model of viscoelastic fluids is proposed. This model takes into account the relaxation time dependence on the shear rate and thereby mimics microscopic processes identified by MCT. Combining this constitutive equation with the Navier-Stokes equations we can describe the evolution of macroscopic flows. Attention will be focused on shear-thinning fluids where the fluid's viscosity decreases with an increasing rate of shear stress.
To solve non-linear integro-differential equations finite element modeling (FEM) is used through a computational fluid dynamics tool. The effect of different relaxation times for a pressure driven flow is studied by analyzing velocity profiles, among other measurable quantities.