Ultrasonic characterization of plastic foams via measurements with static pressure variations

摘要: A method for ultrasonic characterization of plastic foams by changing the static pressure air that saturates foam has been proposed. The is based on high frequency asymptotic expressions standard Johnson–Allard equivalent fluid model. It shown, both experimentally and theoretically, real part squared acoustical refractive index logarithm transmission coefficient depend linearly inverse square root applied pressure. These linear relations provide a simple convenient way to determine constitutive parameters. illustrated with industrial open-cell foams. Advantages, limitations, perspectives are discussed.