Design and research of a torsional vibration absorber based on acoustic black hole

Aiming at the problems of complex structure and limited frequency band in traditional methods for torsional vibration control of shaft systems, a novel torsional vibration absorber was designed based on the acoustic black hole (ABH) effect. By coupling the ABH structure as an additional subsystem to the shaft system, broadband vibration reduction was achieved while ensuring the structural integrity of the shaft. A coupled shaft-ABH beam dynamic model was established, in which the ABH beam features a power-law tapered cross-section designed to effectively transfer and absorb torsional vibration energy from the shaft. The Lagrangian equations of this coupled system were derived based on Timoshenko beam theory and the energy method, building upon the model of the torsional shaft, and an improved Fourier series method was employed to solve its natural characteristics and harmonic responses. A three-dimensional model constructed using finite element software verified the theoretical accuracy. Comparisons between the bare shaft and the shaft equipped with the absorber demonstrated that the ABH structure significantly reduces torsional angular amplitude. Finally, a parametric study systematically investigated the effects of the power-law exponent, installation position, and spring stiffness on the absorber’s performance.