MAE Seminar: Multiscale/Multiphysics Modeling of the Mechanics of Extreme Environment Materials

Abstract: Extreme environment materials present some of the most significant challenges to the development of many advanced technologies in the nuclear, aviation, space, defense, automotive and power-generation industries. Such materials are subject to unprecedented assaults of high thermal heat flux, plasma and nuclear interactions, extremely fast mechanical loads, and erosion and corrosion, to mention a few examples. To meet these challenges, the design methodology must integrate detailed models of the mechanical behaviour of materials together with advanced mechanical design strategies. To accomplish this goal, a multiscale modeling process will be described, where a “top-down” approach is developed that allows incorporation of materials microstructure, and hence manufacturing information, into successively more detailed representations. At the macroscopic level, continuum mechanics is used to couple elasticity and elastoplasticity, while at the mesoscale, microstructure-informed crystal plasticity and discrete fracture mechanics are used; at the nano- and microscales, the method of Discrete Dislocation Dynamics completely resolves the materials microstructure. To endow this multiscale modeling strategy with relevant design attributes, it is embedded within multiphysics FEM-based simulations of coupled fluid mechanics, heat transfer and structural mechanics. Three illustrative examples of the multiscale/multiphysics approach will be presented for the development of: (1) plasma-facing structures in fusion energy; (2) extreme temperature recuperator for hybrid aviation and (3) leading edge of hypersonic vehicles. ​

Bio: Nasr Ghoniem is a distinguished professor in the UCLA Department of Mechanical and Aerospace Engineering, with a joint appointment in the Materials Science & Engineering Department. He has wide experience in the development of materials in extreme environments (nuclear, mechanical and aerospace), and has developed some of the most widely used multiscale computational methods for studies of defect physics and mechanics. Ghoniem is a fellow of the American Nuclear Society, the American Academy of Mechanics, the American Society of Mechanical Engineers, the Japan Society for Promotion of Science and The Materials Research Society. He was the general chair of the Second International Multiscale Materials Modeling Conference in 2004 and is the chair of the 19th International Conference on Fusion Reactor Materials in 2019. He serves on the editorial boards of several journals and has published over 350 articles, 10 edited books, and is the co-author of a two-volume book (Oxford Press) on the mechanics and physics of defects, computational materials science, radiation interaction with materials, instabilities and self-organization in non-equilibrium materials (Oxford Press, 2007, 1100 pages.) He graduated 37 Ph.D. students and 25 postdoctoral scholars (15 are currently in faculty positions). Ghoniem's current research on materials in extreme environments is supported by the National Science Foundation, the U.S. Department of Energy, ARPA-E, and the US Air Force Office for Scientific Research.