סמינר מחלקה של דר' קרלוס פורטלה - "מכניקה של חומרים ארכיטקטוניים על פני טווחי אורך וזמן"
School of Mechanical Engineering Seminar
wednesday, June 8, 2022, at 15:00
Wolfson Building of Mechanical Engineering, Room 206
“Mechanics of Architected Materials Across Length and Time Scales”
Dr. Carlos Portela, MIT (USA)
The lecture is supported by MIT - Israel - MIT-Lockheed Martin Seed Fund
Architected materials have been ubiquitous in nature, enabling unique properties that are unachievable by monolithic, homogeneous materials. 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.
In this talk, we discuss advances in our understanding of architected materials by: (i) proposing numerical and theoretical tools that predict the behavior of architected materials with non-ideal geometries, (ii) presenting a pathway for scalable fabrication of tunable nano-architected materials, and (iii) exploring the response of nano- and micro-architected materials under three types of dynamic loading. We first explore the mechanics of lattice architectures with features at the micro- and millimeter scales, an
discuss the effect of nodes (i.e., junctions) to obtain more accurate computational and theoretical predictive tools. Going beyond lattices, we propose alternative node-less geometries that exhibit extreme mechanical resilience, and we harness self-assembly processes to demonstrate a pathway to fabricate one type in cubic-centimeter volumes while maintaining nanoscale features. Lastly, we venture into the dynamic regime by designing, fabricating, and testing micro-architected materials that exhibit vibrational band gaps in the MHz regime as well as nano-architected materials with extreme energy absorption upon microparticle supersonic impact.
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, and he received degrees in Aerospace Engineering (B.S.) and Physics (B.A.) from the University of Southern California. 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. Present application areas in Dr. Portela’s group involve the creation of novel lightweight armor materials, ultrasonic devices for medical purposes, and new generations of highly resilient structural materials. Dr. Portela 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).
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