Type
Text
Type
Dissertation
Advisor
Chen, Shikui | Wang, Lifeng | Yu, Jie. | Nakamura, Toshio
Date
2017-05-01
Keywords
Mechanical engineering | acoustics metamaterials, architected materials, mechanical, phononic crystals, wave propagation
Department
Department of Mechanical Engineering
Language
en_US
Source
This work is sponsored by the Stony Brook University Graduate School in compliance with the requirements for completion of degree.
Identifier
http://hdl.handle.net/11401/76420
Publisher
The Graduate School, Stony Brook University: Stony Brook, NY.
Format
application/pdf
Abstract
Architected metamaterials with spatially modulated compositions have demonstrated great capabilities to manipulate mechanical wave propagation due to the existence of complete wave band gaps: frequency ranges where mechanical waves are suppressed. The research objective of this thesis is to control undesired vibration using architected metamaterials by integrative design, computational modeling, 3D printing, and mechanical testing. The conflict between mechanical performance and wave energy dissipation limits the potential applications of the passive control technique. The first key objective of this thesis is to resolve this conflict using a system of 3D co-continuous architectures. These co-continuous composites exhibit enhanced mechanical properties including stiffness, strength, energy absorption, and fracture toughness, which are due to the mutual constraints between two phases of the co-continuous architectures. In addition, broad phononic band gaps were observed in this co-continuous metamaterial system, which is due to the overlapping of the Bragg scattering and local resonances. In the complex noise and vibration environmental conditions, it is necessary to selectively control noise and vibration sources over a wide range of frequency. Here, 2D bioinspired architected composites were created by taking inspiration from the inherent architecture of nacreous materials. Broadband and multiple phononic band gaps were reported due to the coexisting of two different physical mechanisms, i.e. | Bragg scattering and local resonances. Moreover, the geometric features of the bioinspired nacreous composites including structural hierarchy and heterogeneity were further exploited to achieve prominent vibration mitigation capabilities. Besides excellent mechanical performance and vibration mitigation capability, lightweight is another criteria that limit the potential deployment of conventional materials. In this regard, lattice materials with different coordinate numbers are more efficient. Here, a group of hierarchical honeycombs was introduced. The introduction of a structural hierarchy into regular honeycombs gives rise to broad and multiple phononic band gaps. Importantly, an inversely proportional relation between relative density and band gap size was observed. As a result, lightweight yet stiff metamaterials can be designed for vibration mitigation. The rest of this thesis will focus on the mechanical tunability of vibration mitigation in a new group of stretchable lattice metamaterials. The proposed lattice metamaterials exhibit broadband vibration mitigation capability, which can be dynamically tuned by an external mechanical stimulus. Experimental studies were also conducted to validate the numerical simulations. The findings presented here will open new avenues to control noise and vibration using architected metamaterial systems. | 166 pages
Recommended Citation
Chen, Yanyu, "Manipulating Wave Propagation Using Architected Metamaterials" (2017). Stony Brook Theses and Dissertations Collection, 2006-2020 (closed to submissions). 2343.
https://commons.library.stonybrook.edu/stony-brook-theses-and-dissertations-collection/2343