Wave propagation and critical conditions for energy focusing pattern transformation in anisotropic fluid-filled porous structures

Abstract

a b s t r a c tConsidering the pore fluid, the energy singular propagation in open-cell anisotropic porous solids is studied with the aim to provide a reference in the energy design and application of porous materials. Firstly, based on Biot's theory, the perturbed eigenvalue problem that arises when the nearly pure modes are propagated is considered. Then, by using the obtained perturbed eigenvalues, the evolution conditions on the elastic parameters of solid skeleton materials are established for the existence of various systems of folds in the wave front. The emphasis is placed on the slow wave, which is particular for the porous material with the pore fluids. The critical conditions for the pattern transformation in the parameter space are given for the first time. Finally, the special situation (zero porosity) is discussed and the comparison with respect to the results for pure solids is made. The results show that the situation in the pure solids is a degenerated case of the present discussion.

Wave propagation in one-dimensional fluid-saturated porous metamaterials

“…Plona 33 and Dutta 34 later proved this fact: the speed of the slow compressional wave is smaller than the speed of sound in the fluid. Wave propagation in FSP media has since then been investigated from different viewpoints and using different methods [35][36][37][38][39] . The effect on the propagation of elastic waves of the material parameters of the fluid, the solid skeleton, and of their combination was discussed.…”

“…The effect on the propagation of elastic waves of the material parameters of the fluid, the solid skeleton, and of their combination was discussed. Slowness surfaces 38 and wave fronts 40 were calculated by using plane-wave theory or characteristic analysis. We note that previous investigations of PCs involving FSP media [22][23][24][25][26] have not specifically considered the possible interference of the two longitudinal waves.…”