Leveraging vibrations, nonlinear dynamics, and wave phenomena in emerging fields and across disciplines

Speaker: Professor Alper Erturk, Georgia Institute of Technology

This talk will review our efforts on exploiting nonlinear dynamics, as well as vibration and elastic/acoustic wave phenomena, in engineering problems. First, we will discuss vibration energy harvesting using piezoelectricity for low-power electricity generation, with a focus on electroelastic dynamics and leveraging designed nonlinearities for bandwidth enhancement, followed by a brief account of inherent material, dissipative, and circuit nonlinearities. Experimental results will be compared against model simulations using the method of harmonic balance. Multiphysics problems of energy harvesting from fluid-structure interaction, and multifunctional concepts such as energy-harvesting bioinspired robotic fish will also be presented. After that, we will discuss mechanical and electromechanical metamaterials and metastructures for vibration/wave attenuation, including a recently introduced general theory, followed by piezoelectric metamaterials with digital programming enabled by synthetic impedance circuits. Bandgap (attenuation frequency range) tuning, rainbow phenomenon, wave compression, wave mode conversion, and reciprocity breaking will be demonstrated for elastic waves through spatial and spatiotemporal programming. Nonlinear metastructures exploiting chaotic vibrations will also be introduced. Our recent efforts on using analog and digital piezoelectric shunt circuits will then be shown for vibration attenuation in structures via concepts like nonlinear energy sink and basic Duffing-type nonlinear circuits. Finally, we will discuss examples on higher frequency problems including gradient-index phononic crystals lens designs for elastic and bulk acoustic/ultrasonic waves, wireless ultrasonic power and data transfer, and leveraging vibrations/vibroacoustics and guided waves in the human skull-brain system.

Prof. Alper Erturk is the Carl Ring Family Chair in the Woodruff School of Mechanical Engineering at Georgia Tech. His theoretical and experimental research interests are in dynamics, vibration, and acoustics of passive and active structures for various engineering problems. His publication/presentation record includes more than 130 journal papers, 220 conference papers/abstracts, 5 book chapters, and 2 books (total citations > 20,000 and h-index: 63). He is a recipient of various awards including the NSF CAREER Award in Dynamical Systems, ASME C .D. Mote Jr. Early Career Award for “research excellence in the field of vibration and acoustics”, ASME Gary Anderson Early Achievement Award for “notable contributions to the field of adaptive structures and material systems”, SEM James Dally Young Investigator Award for “research excellence in the field of experimental mechanics”, and numerous best paper awards including the Philip E. Doak Award of the Journal of Sound and Vibration, among others. He is an Associate Editor for various journals such as Smart Materials & Structures (IOP) and Journal of Vibration & Acoustics (ASME) – and he was recently named the next Editor-in-Chief of Smart Materials & Structures, effective January 2023. He holds Invited/Adjunct Professor positions at Politecnico di Milano (POLIMI) and at Korea Advanced Institute of Science and Technology (KAIST). He is a Fellow of ASME and SPIE .