Date of Award

4-2013

Document Type

Thesis - Open Access

Degree Name

Master of Science in Aerospace Engineering

Department

Aerospace Engineering

Committee Chair

Dr. David J. Sypeck

First Committee Member

Dr. Daewon Kim

Second Committee Member

Dr. Frank J. Radosta

Abstract

Polymers are often used for vibration damping and energy absorption. The effect of a material in reducing the strength of sound waves traveling through it is called acoustic attenuation. In the past, attenuation has mostly been evaluated in the MHz frequency range, using a pulse generator and transmitting transducer as the wave source. However, most real acoustic activities occur at frequencies up to a few hundred kHz. Here, a simple drop ball mechanism is used to generate acoustic source waves in the kHz range, and the attenuation capacities of several solid materials are measured. The recorded waveforms substantially differ between materials. The results show that among the tested polymers, epoxy attenuates the least, rubbers the most, while polyethylene and polyester are also excellent attenuating materials. The drop ball mechanism is controllable and consistent which may be used for other impact or acoustic emission testing. The effect of mixing in additives for the attenuation capacity of epoxy is also investigated.

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