Date of Award

2021

Document Type

Open Access Dissertation

Degree Name

Doctor of Philosophy in Mechanical Engineering-Engineering Mechanics (PhD)

Administrative Home Department

Department of Mechanical Engineering-Engineering Mechanics

Advisor 1

Andrew Barnard

Committee Member 1

Jason Blough

Committee Member 2

Sriram Malladi

Committee Member 3

Scott Wagner

Abstract

Carbon nanotube (CNT) speakers operate on heat as compared to conventional loudspeakers that operate on vibration. CNT speakers are extremely lightweight, stretchable, flexible, and have high operating temperatures. Due to these advantages, CNT speakers are being considered as a viable replacement option for conventional loudspeakers. One such application is automotive exhaust noise control. The goal of this research is to design an enclosed, coaxial CNT speaker and to develop a modeling method to model this speaker using COMSOL Multiphysics.

As part of this research, an enclosed, coaxial CNT speaker was designed and manufactured for automotive exhaust noise control. The first prototype was a proof of concept that the design is feasible, and the speaker works. Two additional prototypes have been developed to improve the manufacturing feasibility and performance.

The first task undertaken during the modeling method development has been to create COMSOL models that simulated the CNT film temperature oscillation and the corresponding SPL. The simulation results have been compared with a MATLAB model for a planar CNT speaker. In addition, the SPL generated by the coaxial speaker has been compared with the simulated SPL generated by the CNT speaker. In addition, the performance of the coaxial speaker has been simulated in the presence of flow. Generally, a good correlation has been observed between the experimental SPL and simulated SPL. The models can be improved with the future development of improved material properties.

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