Flexural wave suppression in periodic rails with Acoustic Black Hole absorbers

The increasing prevalence of railway transportation has exacerbated rail vibration, which predominantly occurs in the wide frequency range of 500–2500 hz. While conventional rail absorbers effectively suppress rail vibration at specific frequencies, broadband suppression remains challenging. An innovative rail absorber utilizing acoustic black hole (ABH) effects is presented in this paper. The absorbers, distributed periodically along the rail length, entail exceptional flexural wave focusing effects through thickness tailoring to the power-law profile. Numerical analyses reveal three distinctive flexural wave suppression mechanisms enabled by this absorber: bandgaps near pinned–pinned resonance frequencies arising from periodically mounting, ABH-enabled broadband energy focusing and damping at medium and high frequencies, and dynamic absorber effects at specific resonance frequencies. The integration of these suppression effects leads to effective broadband rail vibration control. Parametric studies are conducted to provide guidance for absorber optimal design, and experiments validate the effectiveness of the ABH absorbers in broadband rail vibration control, advancing the development of next-generation rail absorbers.