Foundations of Defect Engineering for Dynamic Manipulation of Nonlinear Large-amplitude Waves in Metamaterials
Abstract
Acoustic metamaterials are generally periodic structures assembled using artificially engineered units, and designed to possess unconventional mechanical wave propagation characteristics, with several promising applications. The proposed project aims to understand and exploit the mathematical structure of energy exchange mechanisms between solitary waves and breathers in such metamaterials. Solitary waves are concentrated packets of vibrational energy that can maintain their shape and travel at constant speeds without dispersion, making them ideal carriers of such energy over large distances. One way to manipulate or steer these waves is via purposeful introduction of defects in otherwise periodic lattices built up springs and masses. The presence of a defect gives rise to breathers, i.e., localized, stationary oscillatory defect modes that act as local energy reservoirs. As the wave approaches the defect, a breather can exchange energy with the breather, resulting in complicated and even chaotic dynamics of the wave, leading to capture, transmission or reflection of the wave from the defect site. By appropriately designing the defect and-or providing external actuation to the defect mass, this wave-breather interaction can be tailored to indirectly control the wave. The existing simulation models of wave propagation in systems with such defects are very computationally demanding, and provide little insight into the design and control of structures with embedded defects. The main objectives of the proposed project are 1). To derive simplified models that provide deeper insight into the dynamics of the system, and 2). To develop and experimentally demonstrate control algorithms for on-demand trapping, release, re-direction and mitigation of solitary waves. Specifically, by embedding sensors and actuators at sparse locations in the structure, the complicated dynamics of wave-breather interaction will be exploited in conjunction with opportunistic kicks to the various defect sites in order to demonstrate billiards like trapping of the wave motion within a specific region of the structure. This project will potentially enable design of smart structures with improved stress redirection and concentration, vibration isolation, and mechanical communication capabilities, with applications to national defense, infrastructure resilience, energy harvesting, and space exploration. This work can potentially be applied for deflection and dissipation of severe and complex loading, deployment of multistable structures, and mechanical communication in a variety of DOD relevant applications.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Mar 06, 2024
- Source ID
- FA95502310504
Entities
People
- Piyush Grover
Organizations
- Air Force Office of Scientific Research
- Office of the Secretary of Defense
- University of Nebraska–Lincoln