Place: Seminar room 0.08
Holger Steeb, Ruhr-Universität Bochum, Bochum, Germany
Particular physical properties of materials like negative effective moduli (mass/density, stiffness, electric permittivity and magnetic permeability) have been observed, and physically explained, in various man-made metamaterials. In more or less all cases, these materials are based on periodic (lattice-like) microstructures. In contrast to such man-made materials, the microstructures of geomaterials, like porous rocks or soils, are intrinsically disordered and non-periodic. It will be shown, that a recently proposed multi-phase continuum model, describing acoustic waves in residual saturated porous rocks, is able to determine a similar phenomenon, namely a negative partial density effect close to the resonance frequency of disconnected (non-wetting) fluid phases.
Technically, the presented approach is based on a space-time upscaling technique for multi-phase materials. Therefore, (numerical) homogenization techniques for multi-phase, i.e. fluid-saturated geomaterials will be presented. Further examples for patchy-saturated (bulk-diffusion) and diffusion in fractures will be discussed.