Back analysis of viscoelastic dynamic parametersbased on reflection coefficient measurement
Tao Meng 1,2 Zhao Yang 1
1. School of Mechanical Engineering, Guizhou University, Guiyang 550025;2. State Key Laboratory of Mechanical System and Vibration, Shanghai Jiao Tong University, Shanghai 200240
Abstract:Based on measuring the reflection coefficient of acoustic layer, the back analyzing procedure of viscoelastic dynamic parameters has been developed. In order to get two different reflection coefficients, a periodic cylindrical-hole layer should be measured at two times with different acoustic terminations. Taking account to the analytical relationship between the reflection coefficient and the dynamic parameters of acoustic layer, together using Newton’s method for the nonlinear function of two independent variables, the complex longitudinal wave speed and the complex transverse wave speed will be obtained by solving a series of equations. Furthermore, the complex Young’s modulus and the complex Poisson’s ratio can be calculated easily. Finally, a rubber sample has been tested in the acoustic-pipe, and the identification results of viscoelastic dynamic parameters have been analyzed and discussed.