The 21st International Congress on Sound and Vibration pages:1-8
The 21st International Congress on Sound and Vibration location:Beijing date:13-17 July 2014
In porous materials the frame elasticity and its coupling with the surrounding fluid (e.g. air) are crucial for their sound absorption and transmission. In this contribution the lastic moduli of a porous material are determined. The longitudinal and shear wave velocities of a porous layer are estimated by means of a Lamb model, fitting the experimentally obtained Lamb wave velocity dispersion curves of two propagation modes, S0 and A0, measured over a fre-quency range up to 1400 Hz. The obtained value for the shear wave velocity is shown to be accurate and robust, whilst the extraction of the longitudinal wave velocity is hampered by a large uncertainty. Consequently, the approach allows for an accurate determination of the shear modulus, while the individual estimation of the Young’s modulus and Poisson’s ratio is quite challenging.