The talk
focuses on viscoelastic materials. One of the most modern theories of continuum
mechanics is the multiple natural configurations theory originally developed by
K R Rajagopal. It assumes that as a body is subjected to a thermodynamic
process, the body's underlying natural configuration evolves in such a way that
the rate of entropy production is maximized.
The theory delivers the constitutive equation for the stress tensor in
terms of a tensor related to the natural configurations, tensor that is itself
a solution of an evolutionary equation, so one is confronted to a system of
equations. On the other hand, kinetical theories deliver constitutive equations
in terms of a first statistical momentum the weight function of which is the
so-called configurational probability density (CPD). This CPD is a solution of
a parabolic type PDE which needs to be explicitly solved to obtain the stress
tensor. A comparison and establishing a
link between the two approaches is expected to lead to simplifications in obtaining
the stress tensor for polymeric liquids.