Vibration Damping of Aluminum Plates using Acoustic Black Holes for Application in Aerospace Structures
Open Access
- Author:
- Conti, Angelina Maria
- Area of Honors:
- Aerospace Engineering
- Degree:
- Bachelor of Science
- Document Type:
- Thesis
- Thesis Supervisors:
- Stephen Clarke Conlon, Thesis Supervisor
Dennis K Mclaughlin, Thesis Honors Advisor - Keywords:
- vibration
structures
acoustics
damping
acoustic black hole
acoustic
structure - Abstract:
- In recent years, scientists have investigated the acoustic black hole (ABH) effect as a low-weight high-performance vibration control device for application in aerospace structures. The ABH effect uses a specific power-law skin thickness taper to decrease the velocity of an incident bending wave to nearly zero. Once the velocity has decreased, the wave is unable to reflect back at the far edge, thus trapping it in the ABH. Applying a small amount of viscoelastic damping material to the surface of the ABH dissipates most of the vibration while adding very little weight and cost to the overall structure. Experimental tests prove that the ABH is an effective way to trap and damp vibration energy. The ABH effect is quantified through experimental broadband vibration response comparisons between three aluminum plates of varying degree of vibration control and damping. In general, the low-frequency responses were very similar among all three plates since global modes dominate the response. After the cut-on frequency of the ABH was reached, the ABH effect induced a large variation in the surface averaged mobility, explained by the focusing of energy in the ABH cells. The application of damping material decreased the surface averaged mobility and its variation. Increasing the frequency also decreased the surface averaged mobility variation. These experiments proved that the ABH effect successfully focuses vibration energy from the plate to the center of the two-dimensional ABH and that the added layer of damping material effectively reduces the vibration energy of the structure, while adding very little weight. The ABH could potentially replace traditional heavy and inefficient acoustic treatments, increasing the fuel efficiency by decreasing the weight devoted to acoustic treatment. Future work will include testing an “add-on” ABH device for application in existing airframes.