WAVE PROPAGATION IN MEDIA OBEYING A THERMOVISCOANELASTIC MODEL

The aim of this work is to investigate mechanical phenomenological and state
coefficients taking in account irreversible processes in isotropic viscoanelastic
media of order one. In the contest of Kluitenberg-Ciancio theory we consider the
case of linear transverse acoustic wave of high frequency propagates in such a
medium showing that the aforementioned coefficients assume a particular form as
function of complex wave number. By mean of considerations on linear
phenomenological acoustic theory, we determine a connection between complex
wave number and shear complex modulus, and so we are able to express
phenomenological and state coefficients as function of complex shear modulus. The
experimental knowledge of such a modulus, as function of the frequency, allow us to
experimental evaluation of the aforementioned coefficients. This approach has been
applied to polymeric materials as PolyIsobutilene.