  The mesoscopic concept is a way to deal with complex materials with an
internal structure within continuum mechanics. It consists of extending the
domain of the balance equations by mesoscopic variables and of introducing a
local distribution function of these variables as a statistical element. In our
case microcracks are modelled as penny shaped and completely characterized by
their diameter and the unit normal to the crack surface. Two examples of crack
dynamics are given as well as a possible definition of a damage parameter.
Orientational order parameters (fabric-alignment tensors) are defined and
balance like dynamic equations for them are derived.
