Civil Engineering Seminar Series – Optimal Design Of Micro-Architected Materials

ABSTRACT: Reducing mass without sacrificing mechanical integrity and performance is a critical goal in a vast range of applications. Introducing a controlled amount of porosity in a strong and dense material (hence fabricating a cellular solid) is an obvious avenue to weight reduction. The mechanical effectiveness of this strategy, though, depends strongly on the architecture of the resulting cellular material (i.e., the topology of the introduced porosity). Recent progress in additive manufacturing enables fabrication of macro-scale cellular materials (both single-phase and hybrid) with unprecedented dimensional control on the unit-cell and sub-unit-cell features, potentially producing architectures with structural hierarchy from the nano to the macro-scale. As mechanical properties of materials often exhibit beneficial size effects at the nanoscale (e.g., strengthening of metals and toughening of ceramics), these novel manufacturing approaches provide a unique opportunity to translate these beneficial effects to the macro-scale, further improving the mechanical performance of architected materials. The enormous design space for architected materials, and the strong relationship between the topological features of the architecture and the effective physical and mechanical properties of the material at the macro-scale, present both a huge opportunity and an urgent need for the development of suitable optimal design strategies. This presentation will focus on the optimal design of a variety of lightweight architected materials with unique combinations of stiffness, strength and damping. Different optimal design strategies will be discussed, from geometric optimization of cellular materials with predetermined unit-cell architecture to formal topology optimization of single and double-phase cellular materials with entirely arbitrary architectures.

BIO: Valdevit received his MS degree (Laurea) in Materials Engineering from the University of Trieste, Italy (in 2000) and his PhD degree in Mechanical and Aerospace Engineering from Princeton University (in 2005). He worked as an intern at the IBM T.J. Watson Research Center and as a post-doctoral scholar at the University of California, Santa Barbara. He joined the faculty in the Mechanical and Aerospace Engineering Department at the University of California, Irvine (with a joint appointment in Chemical Engineering and Materials Science) in 2007 and was promoted to Associate Professor in 2013. He is a member of Pi Tau Sigma and Tau Beta Pi and is the recipient of the 2007 Faculty Award from IBM Corporation and the 2012 Popular Mechanics Breakthrough Award. His primary research goal is the optimal design, additive manufacturing and experimental characterization of micro-architected materials with superior combination of properties.