Optimization of Acoustic Black Holes for Vibration Reduction
Open Access
- Author:
- Mc Cormick, Cameron
- Graduate Program:
- Acoustics
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- August 10, 2021
- Committee Members:
- Julianna Simon, Major Field Member
Micah Shepherd, Chair & Dissertation Advisor
Mary Frecker, Outside Unit & Field Member
Stephen Conlon, Major Field Member
Victor Sparrow, Program Head/Chair - Keywords:
- acoustics
optimization
vibration
acoustic black hole - Abstract:
- A problem that frequently arises in noise control engineering is the need for lightweight structures that are also quiet. In many practical instances of transportation and aerospace design, stiff, lightweight panels are used to reduce overall weight. However, these stiff, lightweight panels are also highly receptive to vibration and can become efficient radiators of sound. Although traditional methods of passive damping can effectively combat this behavior, they usually lead to an increase in overall weight. By modifying the plate thickness according to a specific power law profile, so-called `acoustic black holes' (ABHs) offer a compelling solution to the need for both broadband vibration reduction and reduced weight. ABH vibration absorbers have been shown to be effective at reducing structural vibration, often with a net reduction in overall weight. However, a comprehensive understanding of what constitutes optimal ABH design in finite structures has been historically lacking. This dissertation systematically investigates the many considerations of ABH design for vibration reduction. An optimization framework is developed that combines the modelling of structural dynamics with multi-objective evolutionary optimization, and this framework is used to determine the optimal designs for various ABH applications. By analyzing trends in the optimization results, the tradeoffs inherent in ABH design are illuminated in a more holistic manner than has been undertaken to date.