Berlin 2015 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 73: Focus: Disordered Systems/Glasses under Shear (joint session CPP, DY)

CPP 73.5: Vortrag

Donnerstag, 19. März 2015, 16:45–17:00, C 243

Continuum Mechanics Simulations in Glass Forming Liquids — •Heliana Cardenas and Thomas Voigtmann — Deutsches Zentrum für Luft- und Raumfahrt, Köln, Germany

Amorphous glassy materials show complex flow features when they are formed by solidification of dense liquids. An important feature of such systems is the non-linear nature of the flow rule relating stresses and strains when they are perturbed by external forces. The transition itself is characterized by slow dynamics where the intrinsic relaxation time plays a determining role on describing this behavior.

Schematically, the interaction of non-linear rheology and slow relaxation can be captured by so-called ``fluidity" models, where the (spatially local) structural relaxation rate is a function of flow rate. The spatial dynamics of fluidity is controlled by a diffusion coefficient related to a cooperativity length scale.

We use finite volume method (FVM) to combine the resulting constitutive equation with the Navier-Stokes equations to effectively describe the flow behavior of glass-forming systems in various geometries and for different time-dependent protocols.