Volume 80, Number 1, October 2007
Article Number 16003
Number of page(s) 6
Section Condensed Matter: Structural, Mechanical and Thermal Properties
Published online 10 September 2007
EPL, 80 (2007) 16003
DOI: 10.1209/0295-5075/80/16003

Particle displacements in the elastic deformation of amorphous materials: Local fluctuations vs. non-affine field

C. Goldenberg1, A. Tanguy2 and J.-L. Barrat2

1  Laboratoire de Physique et Mécanique des Milieux Hétérogènes (CNRS UMR 7636), ESPCI 10 rue Vauquelin, F-75231 Paris Cedex 05, France
2  Laboratoire de Physique de la Matière Condensée et Nanostructures, Univ. Lyon; Univ. Lyon 1; CNRS UMR 5586, Domaine Scientifique de la Doua - F-69622 Villeurbanne Cedex, France

received 26 April 2007; accepted in final form 13 August 2007; published October 2007
published online 10 September 2007

We study the local disorder in the deformation of amorphous materials by decomposing the particle displacements into a continuous, inhomogeneous field and the corresponding fluctuations. We compare these fields to the commonly used non-affine displacements in an elastically deformed 2D Lennard-Jones glass. Unlike the non-affine field, the fluctuations are very localized, and exhibit a much smaller (and system size independent) correlation length, on the order of a particle diameter, supporting the applicability of the notion of local "defects" to such materials. We propose a scalar "noise" field to characterize the fluctuations, as an additional field for extended continuum models, e.g., to describe the localized irreversible events observed during plastic deformation.

61.43.-j - Disordered solids.
83.10.Bb - Kinematics of deformation and flow.
46.65.+g - Continuum mechanics of solids: Random phenomena and media.

© Europhysics Letters Association 2007