Elastic and acoustic wave propagation in complex media, acoustic metamaterials, new acoustic transduction materials, ultrasonic nondestructive testing, and vibro-acoustic transducers. Modeling, design, and testing of composite materials, metamaterials, and structures. Applications in technical areas that include the absorption and isolation of acoustical, vibrational, and impulsive energy using negative stiffness, acoustic cloaking, and devices that make use of non-reciprocal acoustic and elastic wave phenomena.