Comptes rendus de l academie des sciences serie ii fascicule b-mecanique physique chimie astronomie vol:323 issue:3 pages:177-183
The present Note describes a comparison between experimental data and theoretical predictions for the surface acoustical impedance of fibrous materials used in the automotive industry. The theoretical tool used in this work is the standard Allard-Johnson-Cbampoux model designed for air-saturated materials, which includes 5 parameters, i.e. the porosity, the flow resistivity, the tortuosity, and the two characteristic lengths. The last three parameters are determined with low-frequency ultrasonic techniques. The present comparison, for the first time with fibrous materials, is done with no adjustable parameter, and the agreement is generally excellent.