A Two-Phase Theory for Compaction and Damage

Monday, March 18, 2002 - 1:30pm - 2:30pm
Keller 3-180
Yanick Ricard (École Normale Supérieure de Lyon)
A theoretical model for the dynamics of a simple two-phase mixture is presented. A classical averaging approach combined with symmetry arguments is used to derive the mass, momentum and energy equations for the mixture. Rigorous constraints are used to estimate the form of the averaged stress tensor; it does not involve a bulk viscosity which is often assumed necessary to model compaction. The theory accounts for surficial energy at the interface, and thus pressure differences between phases. We discuss various exemples of compaction or compression of mixture with or without the presence of surface tension. This two-phase theory for compaction and damage employs a nonequilibrium relation between interfacial surface energy, pressure, and viscous deformation and also provides a model for damage (void generation and microcracking) and thus a continuum description of weakening, failure, and shear localization.