Vibration isolator using graded reinforced double-leaf acoustic black holes - theory and experiment

Abstract

The acoustic black hole (ABH) has aroused great interest and shown high potential of application in broadband vibration control using a lightweight structure. Yet conventional ABHs still suffer from intrinsic weak structural stiffness and poor broadband low-frequency performance. Besides, there is a lack of effective computational methods for the design of complex or composite ABH structures with practically required properties. In this paper, the vibration isolation of a beam with embedded graded reinforced double-leaf ABH (GRD-ABH) structures is investigated, focusing on improving both broadband low-frequency vibration isolation performance and the structural stiffness. The multibody system transfer matrix method (MSTMM) is proposed to model and simulate the compound ABH beam, which is treated as a multibody system with complex topology. Both the free and forced vibration analysis of the GRD-ABH are conducted and the results are compared with the finite element method (FEM), thus validating the correctness and high computation efficiency of the MSTMM. The results show that the GRD-ABH beam can simultaneously enhance a broadband low-frequency vibration isolation effect and the structural stiffness compared with the conventional periodic reinforced double-leaf ABH beam. The experiment further verified the correctness of the MSTMM and the effectiveness of the vibration isolation effect of the proposed GRD-ABH beam. The proposed theoretical approach and the graded reinforced double-leaf design provide the basis for solving the vibration isolation problem of more complex ABH structures.