Passive Nonlinear Targeted Energy Transfers

Alexander F. Vakakis

Professor,
University of Illinois at Urbana-Champaign

Seminar Information

Seminar Series
Mechanics & Materials

Seminar Date - Time
May 9, 2022, 2:00 pm
-
3:15

Seminar Location
Seminar Recording - Not Available


Abstract

We explore passive nonlinear targeted energy transfers (TET) in dynamical and acoustical systems based on the synergy of intentional strong nonlinearity, asymmetry, and possible internal scale hierarchy. This is a process where, through predictable design, broadband or narrowband input energy is either irreversibly directed in preferential paths/modes, passively scattered in the frequency/wavenumber domains, dissipated locally, or harvested at a priori designated sites. Interestingly, TET mimics analogous energy cascades occurring often in Nature (e.g., in turbulent flows or granular media), and, as such, benefits from the well-known robust and enhanced dissipative features exhibited by these natural phenomena. Our approach dictates advanced theoretical modelling and analysis accounting for strongly nonlinear effects, but also nonlinear system identification and reduced-order modelling to characterize the experimental realizations that validate the theoretical predictions. We discuss several applications, including implementing intermodal TET, designing, analysing, characterizing, and experimentally testing non-reciprocal lattice materials incorporating internal hierarchical scales, and employing TET for tuning the bandwidths of nonlinear oscillators. The aim is to translate these approaches to new methods, technologies and devices that exploit and showcase nonlinear TET. This work is funded in part by National Science Foundation (NSF) Emerging Frontiers Research Initiative Grant 1741565. Any expressed opinion, findings, conclusions, or recommendations are those of the presenter and do not necessarily reflect the views of NSF.

Speaker Bio

Alexander F. Vakakis received a Ph.D. from Caltech (1990), an M.Sc. from Imperial College, London. UK (1985), and a Diploma in Mechanical Engineering from the University of Patras, Greece (1984). Currently he is the Donald Biggar Willett Professor of the College of Engineering of the University of Illinois at Urbana – Champaign where he co-directs the Linear and Nonlinear Dynamics and Vibrations Laboratory (http://lndvl.mechse.illinois.edu/). Among other awards, he is the recipient of an Alexander von Humboldt Research Award (2019), an Edmond J. Safra Visiting Professorship at Technion (2019), the ASME Thomas K. Caughey Award in nonlinear dynamics (2014), and since 2015 is a National High-End Foreign Expert in China. He has published over 300 archival publications, holds four patents, and has authored or edited 6 technical texts and monographs. Many of his students are now faculty members in the US and abroad, and researchers in R&D centers. His research interests include nonlinear dynamics, vibrations, and acoustics from the macro- to the micro-scales, acoustic metamaterials, nonlinear system identification, bioengineering, non-smooth dynamics and energy harvesting.