Publications

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The phononic dispersion relations calculated by solving an eigenvalue problem while applying Bloch-Floquet boundary conditions are applied to three varieties of phononic pseudocrystals interposers useful for suppressing the transmission of structure-born vibration.

Phase perturbations are used to simulate the time-domain behavior of pressure loads from turbulent boundary layers while faithfully representing the coherence decay behaviors of turbulence-generated pressure fields. Turbulence "evolves" as it proceeds downstream, and coherence decays as the decaying exponential of the product of a flow-related constant with frequency and distance. Time domain methods for a line, a plane, a closed cyclic surface, and most of a cone were given.

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For systems that require complete metallic enclosures, it is impossible to power and communicate with interior electronics using conventional electromagnetic techniques. Instead, pairs of ultrasonic transducers can be used to send and receive elastic waves through the enclosure, forming an equivalent electrical transmission line that bypasses the Faraday cage effect. These mechanical communication systems introduce the possibility for electromechanical crosstalk between channels on the same barrier, in which receivers output erroneous electrical signals due to ultrasonic guided waves generated by transmitters in adjacent communication channels. To minimize this crosstalk, this work investigates the use of a phononic crystal/metamaterial machined into the barrier via periodic grooving. Barriers with simultaneous ultrasonic power and data transfer are fabricated and tested to measure the effect of grooving on crosstalk between channels.

For systems that require complete metallic enclosures, it is impossible to power and communicate with interior electronics using conventional electromagnetic techniques. Instead, pairs of ultrasonic transducers can be used to send and receive elastic waves through the enclosure, forming an equivalent electrical transmission line that bypasses the Faraday cage effect. These mechanical communication systems introduce the possibility for electromechanical crosstalk between channels on the same barrier, in which receivers output erroneous electrical signals due to ultrasonic guided waves generated by transmitters in adjacent communication channels. To minimize this crosstalk, this work investigates the use of a phononic crystal/metamaterial machined into the barrier via periodic grooving. Barriers with simultaneous ultrasonic power and data transfer are fabricated and tested to measure the effect of grooving on crosstalk between channels.

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