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SCHOOL OF MECHANICAL ENGINEERING SEMINAR
Wednesday, March 18, 2020 at 14:00 
Wolfson Building of Mechanical Engineering, Room 206

Beneficial Utilization of Strong Nonlinearity in Dynamics and Acoustics

Alexander F. Vakakis
University of Illinois at Urbana - Champaign, USA
avakakis@illinois.edu

In this lecture we discuss certain examples of beneficial utilization of intentional strong nonlinearity in dynamical and acoustical systems across different scales. Central to this concept is the inducement of irreversible nonlinear energy transfers from large-to-small scales that induce effects such as passive break reciprocity in controlled and predictable ways or broadband / narrowband energy redirection in preferential paths/modes in structures and metamaterials. These non-reciprocal energy transfers mimic analogous energy cascades that occur often in Nature (e.g., in turbulent flows or granular media), and, as such, benefit from the well-known robust and enhanced dissipative features exhibited by these natural phenomena. Our approach dictates advanced theoretical modeling and analysis, but also nonlinear system identification and reduced-order modeling to characterize the experimental realizations that validate the theoretical predictions. In the presented applications, we’ll discuss new approaches for designing, analyzing, characterizing and experimentally testing passive blast mitigation systems, non-reciprocal lattice metamaterials, and fluid control in flow-structure interaction problems. The aim is to translate these methods to new technologies and devices that exploit and showcase intentional strong nonlinearity.
This work is funded in part by National Science Foundation Emerging Frontiers Research Initiative Grant 1741565. Any opinion, findings, conclusions or recommendations expressed are those of the presenter and do not necessarily reflect the views of the National Science Foundation.
Short Bio: Alexander F. Vakakis received his Ph.D. from Caltech (1990), M.Sc. from Imperial College, London (1985), and Diploma in Mechanical Engineering from the University of Patras, Greece (1984). He is the Donald Biggar Willett Professor of the College of Engineering of the University of Illinois where he co-directs the Linear and Nonlinear Dynamics and Vibrations Laboratory (http://lndvl.mechse.illinois.edu/), and currently the Edmond J. Safra Visiting Professor at Technion. Among other awards, he is the recipient of an Alexander von Humboldt Research Award (2019), the ASME Thomas K. Caughey Award in nonlinear dynamics (2014), and since 2015 acts as a National High-End Foreign Expert in China. He has published over 300 archival publications, holds two patents, and has authored or edited 6 technical texts and monographs. His research interests center on nonlinear dynamics, vibrations and acoustics.