Title:

Wave Propagation in Phononic Materials:Effects of Periodicity Type, Properties and Termination

Speaker:

Dr. Mahmoud I Hussein

Affiliation:

Department of Aerospace Engineering Sciences,University of Colorado at Boulder

When:

Friday, January 7, 2011 at 2:00:00 PM   Add to Calendar

Where:

MRDC Building, Room 4211

Host:

Michael Leamy
michael.leamy@me.gatech.edu
404-385-2828

Abstract

In this presentation, we will present a broad overview of elastic wave propagation phenomena in phononic materials with a focus on periodic flexural beams. First, we will present a generalized theoretical formalism for the Transfer Matrix method; based on Timoshenko beam theory, for the analysis of Bloch wave propagation in periodic flexural beams. We will then use this method to explore the effects of different types and properties of periodicity on both propagation and attenuation wave dispersion characteristics. We will consider the following types of periodicities: material, geometric, boundary and suspended mass. Our analysis will focus on the effects on band gaps, and on the conditions for transition between the Bragg scattering and local resonance regimes. We will then consider the important practical problem of the effects of periodicity truncation, whereby we will examine the phenomenon of band gap resonances in finite periodic structures and will discuss their origin, their properties and approaches for their elimination.

Biography

Mahmoud I. Hussien is an Assistant Professor in the Department of Aerospace Engineering Sciences at the University of Colorado at Boulder. He received B.S. and M.S. degrees in Mechanical Engineering from the American University in Cairo (1994) and Imperial College, London (1995), respectively. He also received two M.S. degrees (Applied Mechanics, 1999 and Mathematics, 2002) and a Ph.D. degree (Mechanical Engineering, 2004) from the University of Michigan, Ann Arbor. Following his graduate studies, Dr. Hussein spent a year and a half as a postdoctoral fellow at the University of Michigan, and two years as a research associate at the University of Cambridge’s Department of Engineering. His research focuses on the dynamics of materials and structures with particular attention on periodic materials at both the continuum and atomistic scales. His studies are concerned with physical phenomena governing these systems and relevant theoretical treatments. Recently he has also been conducting experiments to support the theoretical work. In 2005, he received the Robert J. Melosh Medal for Best Student Paper on Finite Element Analysis. Dr. Hussein has authored or co-authored over 40 papers in archival journals and peer-reviewed conference proceedings, and since 2006 has co-chaired nine symposia on “phononic crystals and acoustic metamaterials” at ASME and/or USNCM conferences. He is a co-chair of Phononics 2011 (Sharm El-Sheikh, Egypt, May 29-June 2, 2011), which is poised to become the world’s first conference on the emerging field of “phononics”.

Notes

Refreshments will be served.