SC Colloquium: "A physics-based multi-scale computational framework for partially saturated porous media"
Department of Civil and Coastal Engineering
University of Florida
This seminar includes three parts. In the first part, Dr. Song will introduce a “meso”-scale (i.e. larger than the pore soil particle scale, but smaller than the scale of typical laboratory samples) computational framework for modeling instability of unsaturated soils. In this framework, a porosity-dependent homogenization parameter is used to upscale the strength of a single water meniscus at the pore scale to the strength of unsaturated soils at the continuum scale. This computational framework can capture the material heterogeneities in density and degree of saturation which have been shown to be of great importance to the inception of localized deformation. In the second part of the presentation, Dr. Song will present a recent investigation on the impact of temperature variation on a clay-water-air system at the clay-layer scale (i.e., nano scale) via molecular dynamics (MD) modeling. In this investigation, the water meniscus formed between two parallel pyrophyllite clay particles at different temperatures is studied via MD. This study is focused on the impact of the temperature on the capillary force, contact angle, and meniscus curvature between the two particles under different geometries for the clay-water-air system. The capillary force between clay particles from the MD simulations is compared with results based upon the Young-Laplace equation. This full-scale MD simulation of the clay-water-air system at a finite temperature has a significant implication on formulation of a physically based multi-scale computational framework for unsaturated clays by providing physical properties of such materials at the interfacial scale. In part 3, Dr. Song will discuss the four major challenges regarding multi-scale modeling of multi-phase materials and present a physically based computational framework for modeling three-phase porous media (e.g., unsaturated soils) by integrating molecular dynamics modeling with a multi-phase non-local theory, inspired partially by the “meso”-scale computational framework presented in the first part of the seminar.