Woodruff School of Mechanical Engineering

Faculty Candidate Seminar

Title:

Enhanced Material Nonlinearity and Absorption using Snapping Acoustic Metamaterials

Speaker:

Dr. Michael Haberman

Affiliation:

University of Texas at Austin

When:

Wednesday, September 3, 2014 at 11:00:00 AM

Where:

MRDC Building, Room 4211

Host:

Dr. Kenneth Cunefare
ken.cunefare@me.gatech.edu
404-894-4726

Abstract

Acoustic metamaterials (AMM) are material systems whose overall performance originates from engineered sub-wavelength structure rather than the inherent material properties of their constituents. This relatively new topic in applied physics has garnered attention in the scientific community because of their key role in realizing exotic behavior such as acoustic cloaks, negative refraction, and one-way sound transmission. This work presents a new AMM that is designed to amplify acoustic absorption and nonlinearity for potential use in new acoustical devices and vibro-acoustic coating materials. The AMM consists of a nearly incompressible viscoelastic matrix material containing a low volume fraction of sub-wavelength metamaterial structures (inclusions) that possess a non-monotonic stress-strain response. A nonlinear multiscale material model is presented that captures the strain-dependent evolution of the stiffness of the homogenized medium. That material model is then used to determine the effective quadratic and cubic parameters of nonlinearity of the AMM. Those parameters of nonlinearity are compared with those of conventional materials and examples of one-dimensional wave distortion effects are provided. The forced nonlinear multiscale dynamics in the AMM is then explored using a modified Rayleigh-Plesset model to highlight the influence of inclusion-scale dynamics on macroscopic energy absorbing capabilities for this AMM.


Biography

Dr. Haberman is a Research Scientist with appointments at Applied Research Laboratories and the Department of Mechanical Engineering of the University of Texas at 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. He also 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 transduction materials, ultrasonic nondestructive testing, and vibro-acoustic transducers. He has worked extensively on modeling and characterization of composite materials and multi-objective design of acoustical materials. His current research focuses on analysis, design, and testing of composite materials, metamaterials, and structures to absorb acoustical and vibrational energy using negative stiffness. He is also actively conducting research on transducers that exploit new transduction materials such as single crystal ferroelectric relaxor materials for underwater applications and closed-cell polymer ferroelectret foams for air-coupled ultrasonic applications.

Notes

Refreshments will be served.