The Reddick Lecture: A quiet introduction to acoustic composite materials

Composite multi-phase materials appear everywhere, from electromagnetic coatings, through modern laminates to granular materials. Determining the effective wave propagation characteristics for such composites is often required for evaluation, inspection, or design purposes.

We will focus mainly on simple one-dimensional models that exhibit much of the behaviour found in real materials. By this means we will sketch a common approach employed for composites with periodically arranged microstructure, and then for the scattering properties at the surface of random composites. We will also illustrate how this insight helps in the design of acoustic metamaterials.

David Abrahams is an applied mathematician with research interests in fundamental and applied aspects of wave propagation, diffraction, and scattering. He has published in many areas including aero and underwater acoustics, non-destructive evaluation of materials, linear and nonlinear elasticity, electromagnetics, water waves and seismology. He has interacted extensively with a range of industrial partners, and in recent years his interests have diversified somewhat, ranging from mathematical finance through viscoelasticity to the melting of debris-covered glaciers.

David held the Beyer Chair of Applied Mathematics at the University of Manchester from 1998, and then in 2016 moved to the University of Cambridge to serve as Director of the Isaac Newton Institute for Mathematical Sciences (INI). He has been keen, over many years, to develop links between the mathematical sciences community and industry, commerce, government, and policy makers and he has built up the capacity for knowledge exchange of the International Centre for Mathematical Sciences (ICMS) Edinburgh, whilst serving as as its Scientific Director (2014-16), and of the Newton Gateway to Mathematics, the KE arm of INI.

For his research and community contributions, David was awarded the IMA/LMS David Crighton Medal in 2017 and was made Fellow of the Royal Society of Edinburgh in 2019. On completing his term as INI Director, he will become a Royal Society Industry Fellow at Cambridge University, working with Thales UK on the design of composite underwater coatings.