Development of a Rudimentary Materials Database and Application to the Prediction of Sound Absorptive Performance of Layered Absorbers

Empirical models based on flow resistivity are commonly used to characterize the complex wavenumber and characteristic impedance of common sound absorbing materials such as fibers and foams. The sound absorption of typical sound absorbing materials is measured in an impedance tube and the used to determine a curve fitted flow resistivity via a least squares curve fit. Results for some commonly used sound absorbing materials are tabulated. Additionally, the effect of material compression on the fitted flow resistivity is examined. The database is then used in conjunction with transfer matrix theory to predict the sound absorption of layered absorbers with good agreement to measurement.