HEMI Seminar: Prof. Yida Zhang, “The hidden role of surface forces in the mechanics of porous and granular materials”

The hidden role of surface forces in the mechanics of porous and granular materials

Yida Zhang, Assistant Professor, Geotechnical Engineering and Geomechanics Group, University of Colorado Boulder

JHU Homewood campus, Latrobe Hall, 106

Surface forces in the vicinity of interfaces has been extensively studied in the field of surface science and thin-film physics. Useful concepts such as surface tension and disjoining pressure, however, is seldom linked to the mechanics and physics of porous materials despite their enormous internal surface area (one gram of some porous media can contain surface area as large as a football field). On the other hand, stressed granular materials degrade and creep over time due to grain fracture and breakage at microscale, a process where elastically stored energy is consumed to create new internal areas in the RVE. The role of surface-environment interaction on the fracture/ breakage dynamics in granular systems is currently not well understood.

This presentation will demonstrate how the consideration of solid-fluid interface can explain several characteristic mechanical behaviors of porous and granular materials, including sorption-induced deformation, water-assisted grain crushing, and environment-enhanced fracture propagation. The talk will synthesize the speaker’s past seven years’ effort on this theme and conclude with some future research directions.

Yida Zhang is currently an assistant professor in the geotechnical engineering and geomechanics group at the University of Colorado Boulder. He obtained his PhD degree from Northwestern university in 2016, MS degree from Louisiana State University in 2012, and BS degree from Zhejiang University in 2010, all in civil engineering department. His specialty and research interests are constitutive modeling of geomaterials (soil, rock) interacting with environmental factors (adsorption, dissolution, elevated temperature), granular mechanics, thermodynamics, and energy geotechnics.