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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 7: Soft Matter (joint session CPP/DY)

CPP 7.8: Vortrag

Mittwoch, 29. September 2021, 12:30–12:45, H3

Fluidity models for amorphous glassy materials — •Robin Lautenschlager and Thomas Voigtmann — Institut für Materialphysik im Weltraum, Deutsches Zentrum für Luft- und Raumfahrt (DLR), 51170 Köln

Different rheological models are proposed to describe the complex flow properties of amorphous glassy materials, such as granular materials or colloidal glasses, intermediate between a solid and liquid behavior. These systems show a strong non-linearity due to stresses and strain rates, as well as time-dependent ageing effects. The materials are hence described by a time-dependent local fluidity as a main rheological quantity. Spatial non-localities are quantified by a characteristic cooperativity length that describes the extent over which neighboring material regions influence their flow behavior.

We compare three different approaches of such fluidity models and discuss their key features regarding the complex flow properties and how they try to reproduce the time-dependent effects of such a flow. We probe the models in a pressure driven two-dimensional-channel-flow and compare their long-time numerical results to analytically estimated steady state solutions for this test case. We will discuss how the models respond to different flow properties to evaluate their usability in applications.