Optimal Positioning and Integration of Acoustic Black Holes into Prepared Structures during Early Design Stages

This project is part of the DFG priority programme (PP) 1897: "Calm, Smooth and Smart - Novel Approaches for Influencing Vibrations by Means of Deliberately Introduced Dissipation" In many applications of engineering dissipative effects are often modelled with over-simplification which makes purposeful design of vibrational behaviour difficult or even impossible. Therefore in this PP, the main focus is fundamental research on damping and dissipative mechanisms respectively. The main goal of this PP is to provide the knowledge necessary to optimally exploit dissipative effects in design of dynamic structures. Additional information about the PP "Calm, Smooth and Smart" can be found on the website.

The preparation of a structure in early design stages for upcoming passive damping measures would highly increase the damping effect and decrease costs. More effective damping can be reached by an improvement of the local damper or a modification of wave propagation in the underlying structure. Ideally, those measures should merge in one method. Acoustic black holes are local passive damping systems with an high potential. Artificially created indentations lead to a \\\\\\\\\\\\'trapping\\\\\\\\\\\\' of waves, a reduction of wave speeds and a raise of amplitudes which represents an optimal damping position. The main advantage, which defines acoustic black holes as smart, is a reduction of weight in parallel with a reduction of noise emission. This fact may lessen the conflict between lightweight design and acoustic quality. The full potential of acoustic black holes can only be exploited with a structural integration in early design phases. The impact of a preparation of the underlying structure on localised damping systems is assumed to be crucial and has not been investigated yet. Major objectives of this proposal are two methods concerning the positioning of acoustic black holes within a structure and the integration of acoustic black holes. The latter point is realised by structural modifications leading to a modified wave propagation: The structure-borne energy shall be led to the localised damping treatment in order to exploit acoustic black holes more efficiently. The encompassing and concluding objective of this project is the conflation of these findings regarding positioning and integration. The resulting method will help engineers to consider acoustic black holes in early design phases and to develop a highly efficient and economic calm structure.