Oscillatory measurement of linear viscoelasticity: Dynamic moduli revisited

Abstract

The current technique for the measurement of linear viscoelastic dynamic moduli is reconsidered. The transfer function analysis reveals the existence of nonlinear components in the response of the sample in a wide range of excitation frequencies around the reasonances of the measuring system. This analysis permits the disclosure of the components of the response which behave in accordance to linear viscoelastic theory and separates the undesirable nonlinear components. This results in partial corrections of the anomalous behavior of the calculated dynamic moduli through the standard technique.