Invited seminar at University of Hong Kong

URL: http://www.civil.hku.hk/seminars/20150112-1200.pdf

MULTISCALE MODELING OF STRONG AND WEAK DISCONTINUITIES
IN POROUS MEDIA

by Dr. Steve Sun
Department of Civil Engineering & Engineering Mechanics
Columbia University, USA

Date: January 12, 2015 (Monday)
Time: 12:00 p.m. - 1:00 p.m.
Venue: Room 6-12B, Haking Wong Building
 The University of Hong Kong

ABSTRACT
The mechanical behaviour of a fluid-infiltrating porous solid is significantly influenced by the presence of the pore fluid in the voids. This hydro-mechanical coupling effect can be observed in a wide range of materials, including rocks, soils, concretes, bones and soft tissues. Nevertheless, due
to the high computational demand, explicitly simulating the pore scale solid-fluid interactions of every single grain in the solid skeleton remains impractical for engineering problems commonly encountered in the field and basin scales. The objective of this talk is to present grain- and continuum models that predict and replicate onset of strain localization and fractures in fluid infiltrating porous media. We will first discuss the state-of-the-art mathematical theory and numerical implementation techniques used to model strain localization and fracture of brittle rocks and granular materials undergoing large deformation at the field scale. To improve the understanding of the hydro-mechanical coupling effects in the grain-scale, discrete element model is used and subsequently coupled with continuum models to analyze the onsets and propagations of shear bands and fractures from the microstructural origin. By using a nonlocal homogenization scheme, the discrete-continuum model retains the simplicity and efficiency of the continuum-based finite element model, while possessing the original length scale of the granular system.