A constrained layer damping configuration incorporating acoustic black hole profiles for low-frequency vibration attenuation

Constrained layer damping (CLD) is widely used for structural vibration attenuation; however, its effectiveness in the low-frequency range remains limited. To address this issue, an acoustic black hole (ABH)-profiled constrained layer damping (ABH-CLD) configuration is proposed, in which the damping layer is designed with ABH profiles to enhance low-frequency vibration attenuation. Finite element simulations of beam structures demonstrate that, compared with uniform CLD, the proposed ABH-CLD configuration reduces the first two resonance peak levels by 3.6 dB and 3.7 dB, respectively. Further investigations on plate structures confirm that ABH-CLD can achieve more pronounced attenuation of low-order resonant responses in two-dimensional configurations, with reductions of 3.5 dB and 1.7 dB in the first two resonance peak levels, respectively. The enhanced low-frequency performance is attributed to ABH-induced flexural-wave energy localization and increased viscoelastic shear dissipation in the damping layer, enabling more effective energy dissipation while maintaining comparable overall broadband attenuation performance. In addition, a differential evolution method is employed to optimize the structural and material parameters to improve damping and vibration attenuation.