Seminar by Michael Haberman

Acoustics waves in time-varying and spatiotemporally-varying media

Presented by 
Prof. Michael Haberman from the Walker Department of Mechanical Engineering 

Abstract:

Acoustic and elastic metamaterials with time- and space-dependent material properties have recently received attention as a means to generate nonreciprocal wave propagation or to control the frequency and wavenumber of fields scattered by spatiotemporally modulated (STM) boundaries. This talk begins with an introduction to acoustic wave propagation in materials whose properties are space- and time-dependent, beginning with a cursory summary of wave motion in spatially periodic media. This is followed by a derivation of coupled constitutive relations for the conservation of momentum and mass in materials with spatiotemporally-varying properties and examples of reflection and transmission behavior at “time boundaries” are presented. The more general case of spatiotemporally modulated properties is then presented and discussed in the context of nonreciprocal wave propagation. Lastly, the case of scattering from surfaces with spatiotemporally modulated input admittance is considered. It is shown that one may control the frequency and direction of scattered acoustic fields by changing the amplitude and speed of the admittance modulation. Cases of nonreciprocal and diffusive scattering from the same STM surface with different modulation parameters are then shown and discussed. The talk concludes with a brief discussion of current challenges and future research directions on these topics.

About the Speaker:

Dr. Haberman is an Associate Professor in the Walker Department of Mechanical Engineering at the University of Texas (UT) at Austin with a joint appointment at the Applied Research Laboratories UT Austin. He received his Ph.D. and Master of Science degrees in Mechanical Engineering from the Georgia Institute of Technology in 2007 and 2001, respectively, and received a Diplôme de Doctorat in Engineering Mechanics from the Université de Lorraine in Metz, France in 2006. His undergraduate work in Mechanical Engineering was done at the University of Idaho, where he received a B.S. in 2000. Dr. Haberman's research interests are centered on elastic and acoustic wave propagation in complex media, acoustic metamaterials, new acoustic transduction materials, ultrasonic nondestructive testing, and vibro-acoustic transducers. His current research focuses on modeling, design, and testing of composite materials, metamaterials, and architected media. His research finds application in technical areas that include the absorption and isolation of acoustical, vibrational, and impulsive energy using negative stiffness and Willis coupling, devices that make use of non-reciprocal acoustic and elastic wave phenomena, and condition monitoring of lithium-ion batteries using ultrasonic methods. He is a Fellow of The Acoustical Society of America and served two terms as the chair of the Technical Committee on Engineering Acoustics from 2018-2024.

Date: Tuesday, March 11
Time: 12:00 PM - 1:00 PM
Location: ECJ 3.116

Questions? Contact: Othman Oudghiri-Idrissi, PhD | Assistant Professor