A multidisciplinary effort that emanates from the fusion of the fields of Applied Physics and Materials Science Engineering, to fabricate, test and evaluate state-of-the-art phononic materials and structures that will shield vibrations in multi-scale applications ranging from ultrasonics to earthquake disturbances. Materials by design that rely on the physics of classical spectral-gap materials do have technological advantages over conventional dampers and filters, the most important of which is scalability. To facilitate the structural shielding of sound and vibrations via phononic metamaterials, one can definitely provide the means for efficient industrial and environmental noise reduction, aerospace damping, mechanical stability for precision tools, earthquake and tsunami protection. Thus, phononic metamaterials operating as vibrational mirrors, either functioning independently or in conjunction with each other, would filter out disturbing or dangerous large-scale wave profiles that usually compromise the structural integrity of constructions, proving their usefulness for the world of 21st century.
Unique, cutting edge metamaterials, will be fabricated under the proposed work displaying exciting properties. We will develop new devices able to shield objects from ultrasound and vibration and, most importantly, we will manufacture new structures that enable perfect shielding of constructions from the devastating effects of earthquakes. These new metamaterials will be developed based on the physical picture of the layer-multiple-scattering method (LMS). LMS analysis will drive the engineering of phononic structures with desired properties. Fabrication of real phononic crystal specimens is an indispensable part in this work since it will enable experimental verification of modelled phononic structures.
Finally, to optimize/engineer phononic frequency stop-bands (frequency shields), we will proceed as follows:
- Material moderate damping is an promising tool in further engineering phononic structures to comply with specific needs in complex situations where disturbing localized modes appear inside the gaps.
- Moderate size disorder (Anderson localization of elastic waves) in the building units of a phononic system results in extreme widening of transmission gaps.
- Versatile phononic slabs which are gradient layered heterostructures that can improve the gap width up to 200%, provided the width of the slab is appropriately fabricated to eliminate tunnelling.
- Highly nonlinear phononic granular media can assist for shock energy trapping, redirection and dissipation, as well as phononic defects built to allow only weak energy acoustic modes.