Low-density cellular solids have demonstrated superior mechanical properties as well as multifunctional characteristics, which may provide a basis for the development of novel structured materials. In particular, cellular solids offer great design flexibility, owing to their topology, which can provide desired functionalities via targeted geometric design and proper selection of the constituent material. While stochastic configurations such as metallic foams have proven to be effective for both thermal insulation and mechanical-energy absorption, the topology of deterministic architectures is not constrained by physical processes. This allows for a variety of configurations to be tailored to simultaneously fulfill disparate tasks. An additional aspect of deterministic cellular structures is the possibility of assembling materials or structures by the spatial repetition of a unit cell. The resulting periodicity of such systems simplifies the characterization of physical properties, which can be established by analyzing the unit cell only, and will provide new opportunities in the fields of structural dynamics, where periodicity-induced impedance leads to the control of both constructive and destructive interference on propagating waves.
The objective of this work is to investigate the application of the chiral cellular topology for the design of novel macrostructural, mesostructural and microstructural configurations. A truss-core airfoil, and a truss-core beam are employed as a basis to demonstrate both large-displacement capabilities within the elastic regime of the constituent material, as well as operational deflection shapes with localized dynamic deformations. Large deformation capabilities and unique operational deflection shapes are to be attributed to the unusual deformation mechanism of the chiral lattice. Mesostructural and microstructural configurations, on the other hand, are characterized by an unique mechanical behavior, complex geometry, as well as geometric design flexibility to control both static and dynamic phenomena. The propagation of elastic waves, moreover, is characterized by significant band-gap density as well as strong energy focusing dependent on frequency and wavenumber. These features suggest the chiral topology as a basis for the development of acoustic meta-materials.
| Identifer | oai:union.ndltd.org:GATECH/oai:smartech.gatech.edu:1853/26703 |
| Date | 25 August 2008 |
| Creators | Spadoni, Alessandro |
| Publisher | Georgia Institute of Technology |
| Source Sets | Georgia Tech Electronic Thesis and Dissertation Archive |
| Detected Language | English |
| Type | Dissertation |
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