Viscoelastic modeling of canine vocalis muscle in relaxation.

Analysis of vocal fold vibration requires information on the viscoelastic properties of the vocalis muscle. The force response of two canine vocalis muscles was measured in one-dimensional, stepwise elongation of the tissue as a function of time with a computer-controlled ergometer. The viscoelastic behavior of the muscle in its passive state was demonstrated through the relaxation test. A quasilinear viscoelastic model was used to parametrize the relaxation function, and results are reported for various levels of strain. Furthermore, a model was used to obtain theoretical time-dependent stress-strain curves to compare with experimental data.