One grand challenge for materials and structures design is to satisfy multiple conflicting requirements. For example, energy infrastructure, especially those in remote and extreme environments such as offshore wind turbines and nuclear reactors, requires components to operate effectively over long time periods and avoid catastrophic failures. Structural materials in aviation must be lightweight but high in strength, stiff while dampening out harmful vibrations, survive damaging impact events, and interact with complex flows in non-detrimental ways. On smaller length scales, acoustic and ultrasonic sensors require specific frequency and dissipative responses, and need to detect wavelengths that are much smaller than their physical size. This talk focuses on a common theme to these critical engineering problems: understanding how mechanical waves interact with engineered materials across different length and time scales. In particular, the field of “phononic materials” studies how engineering micro- and meso-scale features in materials and structures can prescribe the frequency and spatial properties of acoustic waves. Features such as spatial periodicity of the material or geometry, resonant inclusions, and nonlinearities can lead to wave propagation and modal properties not found in natural materials. New wave propagation phenomena have been discovered in these material platforms, which has been a direct result of an interdisciplinary research approach, integrating additive manufacturing, acoustics, mechanics, materials science, and design. This presentation will discuss our group’s recent research in phononic materials, focusing on effects of rotation and nonlinearity on wave propagation in phononic materials, using reduced order models, finite element simulations, and experiments. Results demonstrate wave propagation features such as tunable band gaps, energy transfer between modes, non-reciprocal wave propagation, and wave-controlled precision actuation.
About the speaker: Kathryn (Katie) Matlack is an Associate Professor and Richard W. Kritzer Faculty Scholar of Mechanical Science and Engineering at the University of Illinois at Urbana-Champaign, where she leads the Wave Propagation and Metamaterials laboratory. Prior, she received her Bachelor’s degree in mechanical engineering from MIT, her PhD from Georgia Tech, and was an ETH Postdoctoral Fellow at ETH Zurich. Her research group studies how mechanical waves propagate in complex materials over several length scales, and then uses this knowledge to realize new and multi-functional materials, structures, and devices. She is a recipient of Young Investigator Awards from both the Air Force Office of Scientific Research and the Army Research Office, the NSF CAREER award, the ASME CD Mote Early Career Award, and the UIUC Dean’s Award for Excellence in Research. She currently serves as an Associate Editor for the Journal of Nondestructive Evaluation and Wave Motion.
