Research On Structural Vibration Damping Characteristics Based On One-dimensional Acoustic Black Hole Effect

Wave manipulation technique has become a topical issue for sound and vibration reduction in structures in the recent years.The so-called 'Acoustic Black Hole Effect' can reduce edge reflections of flexural waves by changing the local thickness of the structure,which contributes to the vibration reduction in structures.At present,a large number of theoretical models and experiments have been carried out by the researchers to reveal the ABH effect.In this paper,rod of circular cross-section with its local radius changing in the form of a power law profile is proposed to investigate the dynamic vibration characteristics.Firstly,based on the transient dynamics analysis of ABAQUS,the generation mechanism of ABH effect in time domain is researched and the propagation characteristics of the flexural wave in the acoustic black hole structure described by the geometrical acoustic theory is validated.Additionally,by calculating the reflection coefficient based on the separation of the incident and reflected wave,the influence of the small truncation and the damping layer is researched.Secondly,the broadband vibration damping characteristics of ABH rods covered by the damping layer located at its sharp tip is researched based on the steady-state dynamic analysis of ABAQUS and experimental methods.At the same time,the influence of the thickness,distribution and material loss factor of the damping layer on the overall damping effect of the structure is also investigated.Finally,for this kind of ABH rod,two tentative ideas of engineering application are put forward,which have been preliminarily illustrated by the simulation results.The first one is the vibration damping design of some common components according to the structural form.The second one is as a new type of dynamic vibration absorber system attached to the main vibrational structure.