Viscoelastic shear properties of human vocal fold mucosa: Theoretical characterization based on constitutive modeling

The viscoelastic shear properties of human vocal fold mucosa (cover) were p reviously measured as a function of frequency [Chan and Titze, J. Acoust. S ec, Am. 106, 2008-2021 (1999)]. but data were obtained only in a frequency range of 0.01-15 Hz, an order of magnitude below typical frequencies of voc al fold oscillation ton the order of 100 Hz). This study represents an atte mpt to extrapolate the data to higher frequencies based on two viscoelastic theories, (1) a quasilinear viscoelastic theory widely used for the consti tutive modeling of the viscoelastic properties of biological tissues [Fung, Biomechanics (Springer-Verlag, New York, 1993), pp. 277-292], and (2) a mo lecular (statistical network) theory commonly used for the rheological mode ling of polymeric materials [Zhu et al:, J. Biomech. 24, 1007-1018 (1991)]. Analytical expressions of elastic and viscous shear moduli, dynamic viscos ity, and damping ratio based on the two theories with specific model parame ters were applied to curve-fit the empirical data. Results showed that the theoretical predictions matched the empirical data reasonably well, allowin g for parametric descriptions of the data and their extrapolations to frequ encies of phonation. (C) 2000 Acoustical Society of American. [S0001-4966(9 9)06512-1].