Description:

Computational Investigation of Thermo-Mechanical Couplings in Granular Materials Across Scales

Abstract:

Granular materials, such as soils, are abundant on Earth and represent the second most handled substance after water. These materials undergo continuous temperature variations. For example, in the context of geothermal energy harvesting and underground thermal energy storage, soils undergo hundreds of thermal cycles during the lifetime of such systems. Thermal loads produce deformations and changes in the structure and macroscopic properties of soils, whose fundamental governing mechanisms currently remain poorly understood despite their relevance for both science and engineering. In this presentation, two fundamental aspects of the mechanics of granular materials subjected to heat flows are addressed, with a focus on coarse-grained soils. At the microscopic length scale of the particles that constitute coarse-grained soils, Discrete Element Modeling is developed to describe the structural reorganizations caused by cyclic temperature variations and determine the changes in the physical (thermo-hydro-mechanical) properties of such materials through homogenization. At the macroscopic length scale, Multiphysical Finite Element Modeling using an anisotropic plasticity constitutive model extended to account for the effects of temperature is employed to highlight the influence of transient heat flows and boundary conditions on the thermally induced deformation of coarse-grained soils. The findings of this study advance the theoretical understanding of the structure-property relationship of granular materials under non-isothermal conditions and provide new insights to predict and quantify the significant impact of temperature variations on the mechanics of such materials for engineering and industrial applications.

Bio:

Dr. Jibril B. Coulibaly is a post-doctoral fellow in the Department of Civil and Environmental Engineering at Northwestern University. He received his Ph.D. in Mechanics from the Université Grenoble-Alpes, France in 2017. Dr. Coulibaly’s expertise in computational mechanics and software development is supported by a strong academic training in Mathematics and Physics that fuels his creative and multi-disciplinary problem-solving approach. His research interests span the mechanics of deformable structures and solids, as well as, soft and granular matter with an emphasis on both theoretical and computational problems. Dedicated to the betterment of society, his focus ranges from natural hazards mitigation to sustainable infrastructure and renewable energy.