Anisotropic and nonlocal soft acoustic metamaterials
Abstract
The first step of this work is the theoretical and numerical investigation, which will seek to determine the relationships between the arrangement and physical properties of the constituent components with those of the homogenized anisotropic dynamic and nonlocal properties of the proposed soft acoustic metamaterial. A set of numerical experiments will be used to verify the theory of nonlocal acoustic metamaterials, including both general nonlocality and weak dispersion. Second, novel particulate structures will be fabricated and their properties evaluated before addressing complex, multilayered and polydisperse arrangements of particles. The team will propose a set of numerical experiments to test different retrieval methods, based on reflection and transmission coefficient measurement at several angles of incidence. Following this, several numerical experiments, based on the previously computed reflection and transmission coefficients, will be performed to verify the validity of the retrieval method.Following the fabrication and evaluation of the mesoscale particulate structures, the construction and testing of more complex arrangements will be undertaken. Building on the work of the previous stage, multilayered and polydisperse arrangements will be fabricated in order to maximize the anisotropy. These materials will be characterized by means of the retrieval methods developed earlier. The accuracy of the prediction of the effective medium theory will be tested also during this task. Finally, a set of selected samples will be sent to the NRL for their test in the water tank facility. In this way, the far field characteristics of highly anisotropic metamaterials will be tested. Among others, the most interesting effect that it is expected from these structures is a deep sub-wavelength sensibility to the direction of the incident field and, consequently, a strong sub-wavelength anisotropic far-field scattering pattern, allowing for directivity detection at extremely low frequencies.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- May 05, 2017
- Source ID
- N000141712445
Entities
People
- Olivier Mondain-monval
Organizations
- National Center for Scientific Research
- Office of Naval Research
- United States Navy