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

Author(s):  
Jianwang Shao ◽  
Tao Zeng ◽  
Xian Wu ◽  
Jinmeng Yang
2021 ◽  
Vol 184 ◽  
pp. 108342
Author(s):  
Jianwang Shao ◽  
Qimeng Luo ◽  
Guoming Deng ◽  
Tao Zeng ◽  
Jinmeng Yang ◽  
...  

2016 ◽  
Vol 138 (3) ◽  
Author(s):  
Xian Wu ◽  
Jianwang Shao ◽  
Bruno Cochelin

As a new approach to passive sound control in low-frequency domain, the targeted energy transfer (TET) phenomenon has been investigated inside a three-dimensional (3D) acoustic cavity by considering a two degrees-of-freedom (DOF) system with an acoustic mode and a membrane nonlinear energy sink (NES). The beginning of TET phenomenon of the 2DOF system and the desired working zone for the membrane NES have been defined. In order to enhance the robustness and the effective TET range in acoustic cavities, a 3DOF system with two membranes and one acoustic mode is studied in this paper. We consider two different membranes and two almost identical membranes to analyze the TET phenomenon, respectively. The desired working zone which was obtained by the 2DOF system is applied to analyze the 3DOF system. We observe that two membranes can enlarge the desired working zone.


Author(s):  
Pierre-Yvon Bryk ◽  
Sergio Bellizzi ◽  
Renaud Côte

In this paper an electro-Acoustic Nonlinear Absorber (ANLA) is described. It is composed of a baffled nonlinear membrane with its front face coupled to an acoustic cavity and the other one enclosed. The enclosure includes a feedback loop composed of a microphone and a loudspeaker that control the acoustic pressure seen by the rear face of the membrane. Due to the nonlinear geometrical properties of the membrane, the ANLA can synchronize it resonance with one of the resonances of the cavity. It allows to bring out the energy transfer toward the ANLA and thus to reduce pressure in the cavity. The feedback loop tunes the resonance frequency of the ANLA at low level, wich is a key factor for the triggering threshold of the targeted energy transfer. An numerical study of the efficiency of the ANLA to reduce noise in a cavity is presented including the influence of the feedback loop parameters.


Author(s):  
Jianwang Shao ◽  
Xian Wu ◽  
Bruno Cochelin

The targeted energy transfer (TET) phenomenon has been observed in the field of acoustics, which provides a new approach to passive sound control in low frequency domain. The TET phenomenon has been investigated firstly inside one tube (1D acoustic system) with a membrane nonlinear energy sink (NES) or a loudspeaker nonlinear absorber, then inside an acoustic cavity (3D acoustic system) with a membrane NES. 3D acoustic cavities have been considered as more general geometry for the acoustic medium in view of applications in the acoustic field and the membrane NES is mounted directly on the wall of the acoustic cavity. The placement of a membrane NES on the wall involves a weak coupling between the membrane NES and a considered acoustic mode, which constitute the two degrees-of-freedom (DOF) system. The beginning of TET phenomenon of the two DOFs system has been analyzed and the desired working zone for the membrane NES has also been defined. The two thresholds of the zone have been determined by an analytical formula and semi-analytically, respectively. The parametric analysis of the membrane NES by using the two DOFs system has been investigated to design the membrane NES. In order to enhance the robustness and the effective TET range in acoustic cavities, a three DOFs system with two membranes and one acoustic mode is studied in this paper. We consider two different membranes and two almost identical membranes to analyze the TET phenomenon, respectively. The desired working zone for the membrane NES and the value of the plateau which are obtained by the two DOFs system are applied to analyze the three DOFs system. We observe that two membranes can enlarge the desired working zone of the NES.


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