Mechanical and Civil Engineering Seminar

Mechanical and Civil Engineering Seminar Series

Title: Thermo-Mechanics of Granular Materials: Experiments and Eimulations

Abstract:

Granular materials are continuously subjected to temperature variations in nature, industrial processes, and engineering applications. In all of these situations, temperature variations markedly influence the mechanics of granular materials due to a strong interplay between relatively simple temperature effects on single particles and much more complex effects on assemblies of particles, with paramount consequences for natural and engineered systems. This talk presents some of the latest experimental observations and theoretical studies of the thermo-mechanics of granular materials, focusing on the effects of cyclic temperature variations on the structure-property-behavior relationship of sands. Accordingly, this presentation is divided into three parts, each of which addresses the effects of cyclic temperature variations on the structure, properties, and behavior of sands. Through a compendium of results deriving from temperature-controlled computerized tomography and oedometer experiments as well as discrete element and finite element simulations, this work addresses the mechanics of sands subjected to temperature variations across large spatial and temporal scales: from a single sand particle to thousands of such particles and from seconds to centuries. This study indicates that, due to expansions and contractions of their constituents, sands and other granular materials subjected to temperature variations undergo microstructural reorganizations that lead to irreversible macroscopic deformations and changes in the ability of these materials to withstand mechanical loads, allow the permeation of fluids, and transfer heat. Given the relevance of these effects for various natural and engineered systems within the Earth system and beyond, this talk concludes with an outlook on the analyses that the developed competence and tools can serve for the benefit of science and engineering.

Bio:

Dr. Alessandro F. Rotta Loria is an Assistant Professor at Northwestern University (USA), where he directs the Mechanics and Energy Laboratory within the Department of Civil and Environmental Engineering. He received his B.Sc. and M.Sc. degrees in Architectural Engineering from the Politecnico di Torino (Italy) while his Ph.D. degree in Mechanics from the Swiss Federal Institute of Technology in Lausanne, EPFL (Switzerland). His main research interests lie at the intersection of Geomechanics, Energy, and Environmental Sustainability. Dr. Rotta Loria is the co-author of the book "Analysis and Design of Energy Geostructures" (2019, Academic Press). He has co-authored 35 research articles published in international scientific journals, 35 research articles published in conference proceedings, and 1 international patent. Dr. Rotta Loria is Editorial Associate of the international journal Geomechanics for Energy and the Environment and the task force leader of the Academia-Industry Partnership for Innovation on Energy Geotechnics for the International Society for Soil Mechanics and Geotechnical Engineering (ISSMGE). Dr. Rotta Loria is the recipient of several awards, including the Zeno Karl Schindler Foundation Award (2019), the ISSMGE Bright Spark Lecture in Energy Geotechnics (2020), the Promising Investigator Award from the International Association for Computer Methods and Advances in Geomechanics (2021), and the National Science Foundation CAREER Award (2021). In 2021, he was nominated as one of the 100 world innovators under 35 from MIT Technology Review. As a part of his activities, he co-founded two startups: GEOEG and enerdrape.

NOTE: At this time, in-person Mechanical and Civil Engineering Lectures are open to all Caltech students/staff/faculty/visitors.