Woodruff School of Mechanical Engineering

COE/Structural Mechanics Seminar

Title:

Vibroacoustic black holes.Focusing and reciprocity breaking by metacomposites Programming

Speaker:

Dr. Manual Collet

Affiliation:

Ecole central de lyon, Ecully (France)

When:

Thursday, November 1, 2018 at 11:00:00 AM

Where:

MRDC Building, Room 4211

Host:

Massimo Ruzzene
ruzzene@gatech.edu

Abstract

Research activities in smart materials and structures represent a significant potential for technological innovations in many industrial domains. The necessity of controlling vibroacoustic performance of industrial systems motivates a broad research effort for introducing active or passive solutions to control noise and vibrations. After a short introduction and state of art, the presentation describes theoretical and numerical tools for designing adaptive metacomposite through two specific problems: the control of acoustic impedance and of vibrational power flow. In the first part, the concept of active acoustical skin is introduced. Modeling aspects and optimizations tools are also carried out and validated by an experimental prototype. The second part deals with a smart mechanical interface for controlling absorption and transmission of elastodynamic energy by using periodically distributed set of shunted piezoelectric patches. Based on these two concepts, we will present new results concerning potential application on three different aspects. First, we will show how gradient metacomposite made of shunted piezoelectric patches may lead to adaptive lens that can focus flexural waves on dedicated point for SHM scanning or harvesting. On a second part, time-space modulated structures can be programmed inside adaptive metacomposite with suitable technologies. We will give a comprehensive understanding of the induced behaviors. Reflection and transmission of elastic waves incident on dynamic structures are numerically studied. Results show that multiple Bloch modes are stimulated in dynamic structures by incident harmonics, these modes lead to the observed unusual wave conversion phenomena. Finally, an acoustic diode is proposed and an experimentation characterization validates the concept on a rectangular duct.


Biography

Manuel Collet is senior researcher with the French CNRS. He is working with the Tribology and System Dynamics Laboratory (LTDS) of Ecole Centrale de Lyon. Graduating in 1992 with a degree in Mechanical Engineering from Ecole Centrale de Lyon, he obtained his PhD in acoustics from the same university in 1996. His dissertation concerned the Active control of vibrating structures by mean of semi distributed piezoelectric patches. His current research interests focus on smart structures and active control, adaptive materials and metamaterials. He has published more than 75 journal papers, 45 invited conferences, 3 patents with at least 1704 citations. From 1998 to 2013, Manuel Collet was member of the Department of Applied Mechanics of FEMTOST Institute. He was its president of the Scientific Council from 2005 to 2010 and Assistant Director in charge of the scientific strategy and organization from 2008 to 2013. After having spent one year at the Georgia Institute of Technology as a visiting professor in 2006-2007, Manuel Collet created and chaired a new research program concerned with Hybrid Vibroacoustic Interface Control by Metacomposite Optimization. He has been working with the LTDS in Ecole Centrale de Lyon since 2013 and is developing research programs for integrating new class of adaptive metacomposites and developing the associated technologies. He is head of the Dynamics of Complex Structures research team comprising 19 researchers and over 35 PhD students. He is also vice-president of Carnot Institute Engineering at Lyon, member of Board of Directors of Ecole Centrale de Lyon and University of Lyon. As member of ASME Adaptive Structures & Material Systems Branch Committee, he chairs the ASMS symposium during the last SMASIS Conference. He is also expert in different panels as ERC (UE), ANR (FR); AERES(FR), SNSF (CH), NSERC (CA), NSF (US).

Notes

Refreshments will be served.