Joerg Rottler, UBC Department of Physics & Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, B.C. V6T 1Z1, Canada
Amorphous or glassy solids form a large group of materials that include polymeric and metallic glasses, colloidal glasses, foams, emulsions and granular media. Although their many everyday applications rely on the favourable mechanical properties of these materials, the atomic level mechanisms of plasticity are much less understood than in crystals, where plastic flow can be ascribed to the motion of dislocations. The slow flow of amorphous solids exhibits striking heterogeneities: swift localized particle rearrangements take place in the midst of a more or less homogeneously deforming medium. Where do these plastic events occur, and how do they interact? In order to answer the first question, we use molecular simulations of a model glass former and show that structurally weak or 'soft' spots can be identified from the low energy vibrational spectrum of the solid, at which plastic rearrangements occur much more frequently than elsewhere [1,2]. Atomistic simulations, however, are limited to short length and time scales. We therefore propose a mesoscopic model that coarse-grains the material into elastoplastic blocks of the size of a rearranging region. Upon local yielding, these blocks interact instantaneously with an elastic Green's function so that plastic events become correlated in space and time [3]. This model captures all essential aspects of the rheology and plastic correlations observed in the molecular simulation and provides a promising stepping stone towards the development of a complete theory of amorphous plasticity.
- J. Rottler, S.S. Schoenholz, A.J. Liu, Physical Review E 89, 042304 (2014)
- S.S. Schoenholz, A.J. Liu, R.A. Riggleman, J. Rottler, Physical Review X 4, 031014 (2014)
- A. Nicolas, J. Rottler, J-L. Barrat, The European Physical Journal E 37, 1 (2014)
Site web du groupe du Prof. Rottler
Cette conférence est présentée par le RQMP Versant Nord du Département de physique de l'Université de Montréal et le Département de génie physique de Polytechnique Montréal.
