Acoustic Frequency Domain Reflectometry
| dc.contributor.author | Theis, Logan Bartley | en |
| dc.contributor.committeechair | Wang, Anbo | en |
| dc.contributor.committeemember | Manteghi, Majid | en |
| dc.contributor.committeemember | Pickrell, Gary R. | en |
| dc.contributor.committeemember | Zhu, Yizheng | en |
| dc.contributor.committeemember | Jia, Xiaoting | en |
| dc.contributor.department | Electrical Engineering | en |
| dc.date.accessioned | 2024-12-20T09:00:41Z | en |
| dc.date.available | 2024-12-20T09:00:41Z | en |
| dc.date.issued | 2024-12-19 | en |
| dc.description.abstract | Acoustic Frequency Domain Reflectometry (AFDR) is a novel technique employing frequency modulated continuous wave (FMCW) methods in solid acoustic waveguide reflectometry. It is particularly suited to dispersion compensation and phase compensation due to the measurement domain being the frequency domain. This work rigorously analyzes, develops, and experimentally demonstrates AFDR, alongside various compensation methods and demodulation techniques. Distributed measurement of temperature is tested using several novel signal processing algorithms for strain determination and is estimated to have a resolution of 0.58 °C over a 20 cm gauge length. An error correction algorithm to improve SNR in the measurement of strain is proposed and validated. The sensing system has a theoretical spatial resolution of 2 mm and an estimated sensing resolution limit of about 1 cm. AFDR and the associated signal processing developments are positioned to be transformative across many areas of acoustics, with significant potential for distributed sensing along an acoustic waveguide. | en |
| dc.description.abstractgeneral | Acoustic Frequency Domain Reflectometry (AFDR) is demonstrated as a novel method for using acoustic waves to sense different material parameters. Acoustic waves can be guided down various structures, such as a metal wire. Rather than sending out a short burst of acoustic power and analyzing its echoes in the metal wire, this technique uses a constant source of acoustic waves with varying frequency, instead recording how the electrical characteristics of the acoustic source change as frequency changes. Since the measurement is made across frequency, this method is particularly suited to correct for various aspects of the acoustic wave that change with frequency in an otherwise undesirable way. The ability to compensate for acoustic wave speeds that change with frequency as well as imperfections intrinsic to the tuning itself using multiple new methods is demonstrated. Distributed measurement of temperature is tested using various signal processing algorithms, and estimated to have a resolution of 0.58 °C for a 20 cm sensing length. The validated sensing system theoretically has the ability to resolve changes over 2 mm, and the resolution over which sensing may be possible is estimated to be 1 cm. AFDR and the associated signal processing developments are positioned to be transformative across many areas of acoustics, with significant potential for distributed sensing along an acoustic waveguide. | en |
| dc.description.degree | Doctor of Philosophy | en |
| dc.format.medium | ETD | en |
| dc.identifier.other | vt_gsexam:42060 | en |
| dc.identifier.uri | https://hdl.handle.net/10919/123850 | en |
| dc.language.iso | en | en |
| dc.publisher | Virginia Tech | en |
| dc.rights | In Copyright | en |
| dc.rights.uri | http://rightsstatements.org/vocab/InC/1.0/ | en |
| dc.subject | Acoustic Waveguide | en |
| dc.subject | Distributed Sensing | en |
| dc.subject | Dispersion Compensation | en |
| dc.subject | FMCW | en |
| dc.title | Acoustic Frequency Domain Reflectometry | en |
| dc.type | Dissertation | en |
| thesis.degree.discipline | Electrical Engineering | en |
| thesis.degree.grantor | Virginia Polytechnic Institute and State University | en |
| thesis.degree.level | doctoral | en |
| thesis.degree.name | Doctor of Philosophy | en |
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