Design method and vibration reduction mechanism of elastic anti-resonant energy harvester

Objective  Based on the acoustic black hole and anti-resonance theories, this paper presents an elastic anti-resonant energy harvester which is suitable for multi-frequency domain vibration reduction.

Methods By adjusting the structural parameters of the energy harvester, low and medium frequency vibrations on the transmission path and the source of the power equipment can be reduced accurately, addressing the disadvantage of the traditional acoustic black hole structure with poor low-frequency range vibration reduction effects. The Rayleigh method is used to derive the fundamental frequency calculation formula of the energy harvester. The designed multilayer energy harvester is then applied to a standard ship engine room panel and its vibration reduction effect is verified. In accordance with the research results, the vibration reduction rules and effect are analyzed, and corresponding improvements are made.

Results The average vibration speed level near the first resonance frequency of the engine room panel with a nine-layer energy harvester group is reduced by about 8.7 dB, and the peak value of the frequency response curve shows a broadband reduction. By adjusting the size and position of the added mass, the improved multi-mode energy harvester can participate in the vibration reduction of the structure.

Conclusions Compared with the traditional embedded two-dimensional acoustic black hole structure, the elastic anti-resonant energy harvester proposed herein features small additional mass and non-destructive structural strength, and can be designed in any combination, giving it good application value for targeted ship vibration and noise reduction in the low frequency band.