PARTICLE DISPLACEMENTS IN THE ELASTIC DEFORMATION OF AMORPHOUS MATERIALS: LOCAL FLUCTUATIONS VERSUS NON-AFFINE FIELD

摘要

We study the local fluctuations in the particle displacements, defined by subtracting a local, inhomogeneous coarse grained displacement field from the actual displacements, in the elastic deformation of a 2D Lennard-Jones glass. Unlike the commonly studied non-affine field, the fluctuations are highly 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". Preliminary results indicate that localized plastic rearrangements observed in plastic deformation occur in regions of large fluctuations, suggesting a microscopic basis for phenomeno-logical models of plastic flow. We propose a scalar "noise" field to characterize the fluctuations, which may be used as an additional field for extended continuum models.