Parametric studies and optimal design of the exponents collocation of a segmented acoustic black hole beam

Abstract

Acoustic black hole (ABH) is a promising way to deal with the flexural vibration of different structures. By utilizing power-law profiles in extremities of structures, ABH could gradually reduce the phase velocity of the propagating flexural waves and realize the capture of waves in the ABH portion. However, it is difficult to manufacture an efficient ABH extremity in practical implementations, and the existence of truncation always leads to greatly reduction of ABH effect at the range of desired frequencies. In this paper, parametric studies of segmented ABH beams have been carried out to investigate how different ABH portions’ exponents affect the vibration attenuation performance of the segmented ABH beam, thus further optimizing the exponents collocation design to get the better ABH effect around the desired frequencies. The detailed meshing scheme has been first studied to guarantee the accuracy of the numerical simulation model. Then, the mobility of different segmented ABH beams with varying exponents collocations are compared to show the influence of power-law exponent changes of the first and second ABH portions on their vibration attenuation performance. Additionally, the energy ratio and reflection coefficient have also been calculated to reveal the underlying physical mechanism. Furthermore, the radial basis function based neural network and simulated annealing method are used to establish the surrogate model and optimize exponents collocation. The optimized segmented ABH beam exhibits more perfect vibration attenuation performance because of possessing lower reflection coefficient. Finally, an experiment has been completed to validate the optimization result.