Fluid-solid static coupling for saturated porous fiber metals in the Biot's Acoustic Theory

摘要

An extended Fiber Metal Constitutive Model is presented that derives the fluid-skeleton static coupling of Biot's general theory of acoustics for poroelastic medium formed by fiber metal saturated by a fluid. Since the model is developed in the framework of the Biot's general theory, it is also useful when the saturating fluid is a liquid. One parameter is defined to account for the geometric nonlinearities of the solid skeleton. A second parameter is defined to account for intermolecular fluid-solid cohesive forces. Analytical expressions of the 4 constants of the Biot's constitutive model are derived from the two previous parameters, the elastic properties of the base material of the solid skeleton, the elastic properties of the fluid and the porosity. Analytical solutions are developed for the reflection and absorption coefficients. The model and the analytical solutions are validated against experiments in the impedance tube in a frequency range from 100 to 6000 Hz for a metal fiber skeleton saturated by air. Simulations are performed for a metal fiber skeleton saturated by a liquid in order to highlight the implications of the wave that propagate by the solid skeleton in the acoustic behaviour.