Atomic-scale origin of dynamic viscoelastic response and creep in disordered solids
View / Open Files
Authors
Milkus, R
Zaccone, Alessio
Publication Date
2017-02-01Journal Title
Physical Review E
ISSN
2470-0045
Publisher
American Physical Society
Volume
95
Number
023001
Language
English
Type
Article
This Version
AM
Metadata
Show full item recordCitation
Milkus, R., & Zaccone, A. (2017). Atomic-scale origin of dynamic viscoelastic response and creep in disordered solids. Physical Review E, 95 (023001)https://doi.org/10.1103/PhysRevE.95.023001
Abstract
Viscoelasticity has been described since the time of Maxwell as an interpolation of purely viscous and purely elastic response, but its microscopic atomic-level mechanism in solids has remained elusive. We studied three model disordered solids: a random lattice, the bond-depleted fcc lattice, and the fcc lattice with vacancies. Within the harmonic approximation for central-force lattices, we applied sum rules for viscoelastic response derived on the basis of nonaffine atomic motions. The latter motions are a direct result of local structural disorder, and in particular, of the lack of inversion symmetry in disordered lattices. By defining a suitable quantitative and general atomic-level measure of nonaffinity and inversion symmetry, we show that the viscoelastic responses of all three systems collapse onto a master curve upon normalizing by the overall strength of inversion-symmetry breaking in each system. Close to the isostatic point for central-force lattices, power-law creep G(t) $\sim$ t$^{−1/2}$ emerges as a consequence of the interplay between soft vibrational modes and nonaffine dynamics, and various analytical scalings, supported by numerical calculations, are predicted by the theory.
Identifiers
External DOI: https://doi.org/10.1103/PhysRevE.95.023001
This record's URL: https://www.repository.cam.ac.uk/handle/1810/263168
Rights
Licence:
http://www.rioxx.net/licenses/all-rights-reserved