Dresden 2011 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 30: Complex Materials

MM 30.1: Talk

Wednesday, March 16, 2011, 16:15–16:30, IFW D

Numerical solutions of the elastodynamic equations for icosahedral quasicrystals — •Frohmut Rösch and Hans-Rainer Trebin — Institut für Theoretische und Angewandte Physik, Universität Stuttgart, Germany

The vibrational properties of most solids can be characterized by the time evolution of the phononic displacements u(x,t). In quasicrystals, however, additional degrees of freedom must be taken into account, which are described by the so-called phasonic displacements w(x,t). The latter are related to flips of atoms in the atomic picture.

The governing equations, which describe the dynamic behavior of both u and w, are extensions of the elastodynamic equations for crystals generalized by the phasonic degrees of freedom. These result in propagating (phonon-like) and diffusive (phason-like) elementary modes.

A finite element package has been adjusted to solve the elastodynamic equations for a three-dimensional icosahedral quasicrystal. Fundamental scenarios, e.g. the time evolution of phason and phonon excitations in a finite sample, are investigated and compared to analytic solutions.