INTERNAL-FRICTION OF A LINEAR VISCOELASTIC SOLID WITH A DISTRIBUTION OF RELAXATION-TIMES

The dynamical response of a linear viscoelastic solid, when a distribution of relaxation or retardation times is present, is studied in detail. It is shown how the internal friction or loss tangent can be expressed in terms of the expression for a standard anelastic solid, using a distribution which is related to the original distribution of relaxation or retardation times, introduced into the dynamical moduli or compliances, respectively. The internal friction is analyzed both as a function of temperature or the frequency and the concepts developed in the paper are applied to actual experimental data for the Snoek relaxation in Nb-O alloys.