Elasto-Dynamic Behavior of a Two-Dimensional Square Lattice With Entrained Fluid II: Microstructural and Homogenized Models

摘要: This paper presents a detailed study of the pressure waves and effective mechanical properties closed-cell cellular solid with entrained fluid. Plane-harmonic-waves are analyzed in periodic square finite-element model representative-volume element, which explicitly considers fluid-structure interactions, structural deformations, fluid dynamics The wall, cavity, coupled-system resonance frequencies identified as key parameters that describe propagation characteristics. A tube-piston based on computed microstructural deformations allows us to determine stiffness tensor an equivalent continuum at macroscale. analysis dispersion surfaces indicates single isotropic mode for below lattice walls, unlike Biot's theory predicts two modes. Shear modes instead strongly anisotropic all values relative density rho* describing both = 0.3. dependence wave phase velocity is varying Depending mass coupling phases, can be three types: bending, through-the-thickness, combination two. For heavy stiff fluid, bending regime confined extremely small density, whereas light such gas, bending-type < 0.1. Through-the-thickness appear only large rho*.