Obiettivo
This work aims at the development and implementation of hierarchical computational approaches for predicting the thermodynamic and structural properties of glasses based on their composition and on the conditions of their formation. The atomistic configuration of a glassy material is envisioned as being trapped in the vicinity of local minima of the potential energy for long periods of time. Physical ageing and plastic deformation in response to externally imposed stress fields result from successive infrequent transitions between neighbouring local minima. Rate constants for these transitions will be obtained atomistically through multidimensional Transition State Theory (TST).
New TST-based simulation methods will be developed in order to study:
(1) physical ageing (distributions of relaxation times and atomic displacements, temporal evolution of volume, enthalpy, and distribution of accessible volume);
(2) the response to large-strain mechanical deformations (stress-strain curve, yield point, evolution o f structural characteristics).
Two types of systems will be studied:
(a) mixtures of Lennard-Jones spheres, as a model for small-molecular weight glassy materials;
(b) atactic polystyrene.
The effects of temperature, history of vitrification and deformation rate will be quantified. Direct comparisons with experimental data will be performed.
Campo scientifico
Parole chiave
Invito a presentare proposte
FP6-2002-MOBILITY-11
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Meccanismo di finanziamento
ERG - Marie Curie actions-European Re-integration GrantsCoordinatore
ZOGRAFOS/ATHENS
Grecia