Dresden 2014 – wissenschaftliches Programm
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DF: Fachverband Dielektrische Festkörper
DF 28: Slow Dynamics in Glasses and Granular Matter II (Joint Focus Session with DY and CPP)
DF 28.4: Vortrag
Freitag, 4. April 2014, 10:30–10:45, HÜL 186
Granular matter composed of shape-anisotropic grains under shear — Ralf Stannarius1, Sandra Wegner1, Tamás Börzsönyi2, and •Balázs Szabó2 — 1Inst. of Experimental Physics, University of Magdeburg, Germany, — 2Institute for Solid State Physics and Optics, HAS, Budapest, Hungary
This contribution establishes a link between two different soft matter systems that can develop orientational order, liquid crystals and granular matter. We present shear experiments with prolate (ellipsoids, cylinders) and oblate (lentils) particles and discuss the observed order and alignment. Positions and orientations of the individual grains in the bulk are resolved by X-ray tomography. Shear experiments show that many observations are qualitatively and even quantitatively comparable to the behavior of the well-understood molecular liquid crystal mesophases, even though the types of interactions are completely different. We establish a quantitative relation between shear alignment and aspect ratio and investigate the interrelations to shear dilatancy and macroscopic friction properties. Long-range effects like particle rearrangements by creeping motion far from the shear band are detected.