Acoustic Materials and Metamaterials

The study of electromagnetic and acoustic waves is an endeavor that dates back centuries. An important subdomain of this field that affects our daily life is the use of acoustic principles to control environmental noise. In this regard, acoustic materials, which are materials designed to manipulate sound wave propagation, are of prime importance. Within this field, about three decades ago, the concept of metamaterials was proposed that has created a revolution. Theoretical formulation and experiments have shown the feasibility of realizing man-made acoustic metamaterials that can manipulate waves beyond the defined limits of those found in nature. Therefore, within a time span of 15 years, acoustic materials have emerged as an active field driven by scientific discoveries and diverse application potentials in machinery noise control, frequency filtering, speech transmission technology, acoustic imaging, and cloaking. This is the first-ever organized coursework on acoustic materials with a special focus on acoustic metamaterials. This course will cover the following topics: 1) Acoustic fundamentals. 2) Theory and design principles of acoustic barrier materials, sound absorbing materials. 3) Limitations of conventional materials. 4) Principles of acoustic metamaterials. 5) Theory and design principles of membrane type metamaterials, of sonic crystals. 6) Guidelines for selecting acoustic materials. (from nptel.ac.in)