The vibration of and wave propagation in periodic cellular structures
are analyzed. Cellular structures exhibit a number of desirable
multifunctional properties, which make them attractive in a variety of
engineering applications. These include ultra-light structures, thermal
and acoustic insulators, and impact amelioration systems, among others.
Cellular structures with deterministic architecture can be considered
as example of periodic structures. Periodic structures feature unique
wave propagation characteristics, whereby elastic waves propagate only
in specific frequency bands, known as "pass band", while they are
attenuated in all other frequency bands, known as "stop bands". Such
dynamic properties are here exploited to provide cellular structures
with the capability of behaving as directional, pass-band mechanical
filters, thus complementing their well documented multifunctional
characteristics.
This work presents a methodology for the analysis of the dynamic
behavior of periodic cellular structures, which allows the evaluation
of location and spectral width of propagation and attenuation regions.
The filtering characteristics are tested and demonstrated for
structures of various geometry and topology, including cylindrical
grid-like structures, Kagom and eacute; and tetrhedral truss core lattices.
Experimental investigations is done on a 2-D lattice manufactured out
of aluminum. The complete wave field of the specimen at various
frequencies is measured using a Scanning Laser Doppler Vibrometer
(SLDV). Experimental results show good agreement with the methodology
and computational tools developed in this work. The results demonstrate
how wave propagation characteristics are defined by cell geometry and
configuration. Numerical and experimental results show the potential of
periodic cellular structures as mechanical filters and/or isolators of
vibrations.
| Identifer | oai:union.ndltd.org:GATECH/oai:smartech.gatech.edu:1853/7122 |
| Date | 19 May 2005 |
| Creators | Jeong, Sang Min |
| Publisher | Georgia Institute of Technology |
| Source Sets | Georgia Tech Electronic Thesis and Dissertation Archive |
| Language | en_US |
| Detected Language | English |
| Type | Dissertation |
| Format | 31162266 bytes, application/pdf |
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