Design optimization and performance comparison of three styles of one-dimensional acoustic black hole vibration absorbers

Structures whose thickness is tapered according to a power law exhibit the ‘acoustic black hole’ (ABH) effect, which can be leveraged for effective vibration reduction without a net increase in weight. However, classic ABH theory is not explicit about the precise topology of the taper, which may have significant practical effects in structures containing ABHs. In this paper, three styles of one-dimensional ABH vibration absorbers are examined, referred to herein as ‘standard symmetric’, ‘standard nonsymmetric’, and ‘double-leaf’. Each style of ABH is embedded in a beam and a multi-objective approach is used to identify the set of ABH designs that optimally minimize the beam's vibration response and its overall mass. Comparison of the results show that each style of ABH has a similar trade-off between the two objectives, but that the choice of style – particularly as regards the application of added damping – can have significant effects on overall performance.