Lightweight-high-stiffness vibration insulator with ultra-broad band using graded double-leaf acoustic black holes

A lightweight-high-stiffness beam insulator embedded with graded double-leaf acoustic black holes (G-DABHs) was designed and fabricated to mitigate broadband low-frequency vibration. The insulator, over 40% lighter than the regular beam, exhibits ultra-broadband low-frequency vibration insulation performance with average transmission of 0.8% (635 Hz-20 kHz) or lower if it becomes a bit lossier. This exotic insulation arises from multimodal-And-coupled-multimodal wave trapping by the G-DABHs and amplified dissipation due to metadamping occurrence. The insulator also exhibits both broader vibration damping and higher static stiffness compared with conventional periodic ABH-beam-counterparts, and thus provides a lightweight-And-high-stiffness solution for ultra-broadband low-frequency vibration control.