Voigt model based ultrasound vibrometry method can be utilized to measure shear mechanical properties of materials or biological tissue quantitatively and invasively. But Voigt model cannot describe stress relaxation of medium. In order treat this problem, a more generalized model, Zener model, was used to represent complex viscoelastic behavior of isotropic and incompressible viscoelastic medium. Based on Zener model, the shear wave propagation velocity was derived from the wave equation and the constitutive relation of Zener model. The shear modulus was estimated from velocity by mathematical method. Shear wave velocities in gelatin and rubber were obtained.Voigt and Zener model were utilized to fit the velocities, respectively, and the results demonstrated that Zener model is better for characterization.
