Influence of the pre-stress of the nonlinear membrane absorber for targeted energy transfer applied to 3D acoustic cavity

Abstract

The targeted energy transfer (TET) technique could be applied to reduce the low frequency noise by a nonlinear membrane absorber as nonlinear energy sink (NES) inside a tube or an acoustic cavity. The pre-stress of the nonlinear membrane can affect the desired working zone for the TET and also the suppressed amplitude of noise. In order to design the nonlinear membrane according to a given acoustic medium, the influence of the pre-stress of the nonlinear membrane is quantitatively studied in this paper. The analytical formulae over the pre-stress of the membrane are established based on a general model of the system with an acoustic mode of 3D acoustic cavity and one membrane. Meanwhile, the suppressed frequency bandwidth of noise is investigated under different pre-stress levels of the membrane by using harmonic balance method and numerical method. For convenient applications, the radial deformation analysis and the modal analysis of the membrane with the prestress are finally performed by finite element method (FEM) to obtain the relationship between the radial displacement and the first mode. It can be helpful to guide design of the pre-stress of the membrane NES according to the desired working zone for the practice engineering application in acoustic field.

Realization of nonreciprocal acoustic energy transfer using an asymmetric strong nonlinear vibroacoustic system

“…A tunable NES 31 was constructed by coupling a speaker with a linear acoustic system, and a system with multiple nonlinear membranes 32 arranged in parallel improved the efficiency and robustness of the targeted energy transfer. At the same time, the broadband sound absorption performance of the large-amplitude nonlinear vibrating membrane [33][34][35][36] was studied. These studies show that directional transmission of acoustic waves can be realized by using an NES, which provides a new method for low-frequency noise control.…”

Influence of Boundary Impedance of 3D Cavity on Targeted Energy Transfer between a Damped Acoustic Mode and a Nonlinear Membrane Absorber

“…Subsequently, based on the research of the two DOFs system, they optimized the material parameters, structure size parameters and installation position of the NES that affect the TET phenomenon [21]. Then they deduced the theoretical formula of the beginning and ending TET thresholds and analyzed the influence of the pre-stress on the first mode frequency of the membrane and the frequency bandwidth of the TET [22]. Bryk et al [23] combined active feedback control with passive NES and proposed a new type of electroacoustic nonlinear membrane absorber which can change the system resonance frequency by controlling the feedback gain and adjust the threshold that triggers off the TET phenomenon.…”