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

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. Copyright (C) EPLA, 2007.