“Mechanics of Architected Materials Across Length and Time Scales”
Abstract: Inspired by natural processes, human-made three-dimensional (3D) architected materials have been reported to enable novel mechanical properties such as high stiffness-to-density ratios or extreme resilience, increasingly so when nanoscale size effects are present. However, most architected materials have relied on advanced additive manufacturing techniques that are not yet scalable and yield small sample sizes. Additionally, most of these nano- and micro-architected materials have only been studied in the static regime, leaving the dynamic parameter space unexplored. To enable widespread use of architected materials beyond laboratory conditions, understanding their mechanical response across length and time scales is necessary. In this talk, we discuss efforts to expand our understanding of architected materials via two paths: (i) fabrication and mechanical characterization of aperiodic nano- to microscale morphologies obtained via scalable self-architecture processes, and (ii) mechanical characterization of nano- and micro-architected materials under dynamic loading. To enable scalable architected materials across length scales, we harness self-assembly processes such as polymerization-induced phase separation to fabricate bicontinuous nano-architected materials with up to cubic-centimeter volumes. We present an experimental and computational framework to relate the geometry—specifically the curvature of domains—to the resulting macroscale mechanical properties. Specifically, we will discuss how the morphology of doubly curved interconnected shells serves as an indicator for elastic anisotropy and predictions of the onset of nonlinearity. In the dynamics regime, we present an experiment-informed dimensional analysis framework that predicts the role of microstructure on the energy dissipation response of micro-architected materials, specifically under supersonic microparticle impact. Lastly, we will discuss efforts performing non-contact mechanical characterization of architected materials by leveraging laser-induced wave propagation. Together, these efforts aim to push our mechanical understanding of architected materials beyond quasi-static conditions and microscopic sample sizes, in a manner that is applicable to architected materials across length scales and independent of fabrication methods.
Bio: Carlos Portela is the d’Arbeloff Career Development Professor in Mechanical Engineering at MIT. Dr. Portela received his Ph.D. and M.S. in mechanical engineering from the California Institute of Technology, where he was given the Centennial Award for the best thesis in Mechanical and Civil Engineering. His current research lies at the intersection of materials science, mechanics, and nano-to-macro fabrication with the objective of designing and testing novel materials—with features spanning from nanometers to centimeters—that yield unprecedented mechanical and acoustic properties. Dr. Portela’s recent accomplishments have provided routes for fabrication of these so-called ‘nano-architected materials’ in scalable processes as well as testing nanomaterials in real-world conditions such as supersonic impact. Dr. Portela was recognized as an MIT TR Innovator Under 35 in 2022, is a recipient of the 2022 NSF CAREER Award, the 2019 Gold Paper Award from the Society of Engineering Science (SES), and his work has been featured in The National Nanotechnology Initiative Supplement to the President’s 2020 Budget (National Science and Technology Council).