📆 Friday, November 8, 2024

🕐 12:00 pm CET

📍 OCZ Room, C1 building, 2nd floor, CIMNE Barcelona (UPC Campus Nord)

ABSTRACT

Granular materials, ranging from soils and food grains to construction aggregates and pharmaceutical powders, are prevalent in both natural and industrial contexts. Their complex physical behavior, which can exhibit both solid- and fluid-like properties depending on several external and internal factors, arises from their discrete composition, characterized by intricate particle interactions. This complexity is further amplified by thermal effects, which explains the current gaps in achieving a comprehensive understanding of the thermomechanics of granular matter. This thesis explores the thermomechanical behavior of granular media from different perspectives, including numerical and experimental analyses. In particular, two key thermal effects are addressed throughout the research, namely, heat generation from mechanical energy dissipation and thermal expansion in confined systems. In the physical experiments, the heat generation phenomenon is studied for granular mixing operations using two widely-used industrial devices: a rotating drum and a bladed mixer. In both setups, the temperature rise of granular flows is measured under varying operational conditions. Regarding numerical investigations, two approaches are developed. An efficient Discrete Element Method (DEM) framework is used to investigate heat generation mechanisms and provide insights into the thermomechanical behavior of granular flows. Additionally, a novel multiscale numerical framework is developed, coupling continuous and discrete methods through a machine-learning-based surrogate model, to efficiently simulate thermal expansion in confined granular media. In both strategies, the underlying objective is to reduce the high computational cost of simulating granular media, allowing for large-scale analyses in terms of both time and space.

Committee

• President: Dr. Jerzy Rojek
• Secretary: Dr. Javier Bonet
• Member: Dr. Wei Wu
• PhD advisors: Dr. Alessandro Franci, Dr. Eugenio Oñate

PHD CANDIDATE

Mr. Rafael Rangel is with the Structural Mechanics research group, part of CIMNE's Structural and Particle Mechanics research cluster.