A FINITE STRAIN ELASTIC-PLASTIC MODEL FOR THE QUASI-STATIC BEHAVIOUR OF PARTICULATE COMPOSITES

摘要

The quasi-static behaviour of a propellant-like material is studied. A Lagrangian finite strain elastic-plastic model is proposed. Employment of logarithmic strain is followed by elastic-plastic additive decomposition. The plastic deformation is split in volumetric and distorsional parts which constitute two distinct state variables for the compaction (matrix compressibility) and yielding (aggregate deformation) considered as separate mechanisms. A thermodynamic potential generates the rubber-like elastic behaviour. The elastic moduli are assumed to depend on plastic volumetric deformation; this is linked to some energy release, accounted for in the compaction model. The yielding mechanism is described by a non-associated flow rule. The model conveys significant geometrical and mechanical coupling effects.