Increased modal damping of undamped single and multiscale acoustic black hole panels

The acoustic black hole (ABH) effect has been shown to increase damping of structures by focusing energy into a tapered-thickness region with added damping material. This paper illustrates that enhanced damping can be achieved without the use of damping material. Three panels were designed with different ABH grid patterns and parameters and compared to a baseline panel. Increased damping is shown to exist for two of the three ABH panels even though no damping material was applied. The panel modes which exhibited increased damping were local to the ABH grid while global modes did not exhibit increased damping.