Study of Targeted Energy Transfer Inside 3D Acoustic Cavity by Two Nonlinear Membrane Absorbers

2015 ◽  
Author(s):  
Jianwang Shao ◽  
Xian Wu ◽  
Bruno Cochelin
Keyword(s):  
Energy Transfer ◽  
Degrees Of Freedom ◽  
Analytical Formula ◽  
Acoustic Mode ◽  
Acoustic Medium ◽  
Targeted Energy Transfer ◽  
Acoustic System ◽  
Working Zone ◽  
Acoustic Cavity ◽  
Acoustic Cavities

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.

Study of Targeted Energy Transfer Inside Three-Dimensional Acoustic Cavity by Two Nonlinear Membrane Absorbers and an Acoustic Mode

2016 ◽  
Vol 138 (3) ◽  
Author(s):  
Xian Wu ◽  
Jianwang Shao ◽  
Bruno Cochelin
Keyword(s):  
Energy Transfer ◽  
Degrees Of Freedom ◽  
Three Dimensional ◽  
Low Frequency ◽  
Nonlinear Energy Sink ◽  
Acoustic Mode ◽  
Targeted Energy Transfer ◽  
Working Zone ◽  
Acoustic Cavity ◽  
Acoustic Cavities

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.

Study on target energy transfer of 3D acoustic cavity - plate coupling system with the membrane nonlinear energy sink

2021 ◽  
Vol 263 (1) ◽  
pp. 5891-5901
Author(s):  
Jinmeng Yang ◽  
JianWang Shao ◽  
GuoMing Deng ◽  
Xian Wu
Keyword(s):  
Energy Transfer ◽  
Sound Pressure ◽  
Single Point ◽  
Nonlinear Energy Sink ◽  
Coefficient Matrix ◽  
Acoustic Medium ◽  
Acoustic Cavity ◽  
Target Energy ◽  
Energy Sink ◽  
Nonlinear Energy

The target energy transfer (TET) between a membrane nonlinear energy sink (NES) and the acoustic medium inside a rectangular cavity is studied. The acoustic medium is interacted with a plate and multi-order modes coupling of the 2 structure is considered. Based on the modal expansion approach, with Green's function, Helmholtz equation and the boundary conditions of the acoustic medium and the plate, the coupling coefficient matrix of the mode of 2 structures is derived. The equations of the membrane NES, multi-order modes of the acoustic medium and multi-order modes of the plate are established, and numerical analysis is used to investigate the TET phenomenon. The results show that in condition of a single-point excitation to the plate, under a certain range of excitation levels, the membrane can be seen as a kind of NES, and the energy in the acoustic medium can be unidirectionally transmitted to the membrane NES and attenuated, reducing the sound pressure level in the cavity. At the same time, it is found that the NES can suppress multi-order sound pressure of the acoustic medium at the same time, and realize the control of cascaded resonance noise.

Targeted energy transfer in a 2-DOF mechanical system coupled to a non-linear energy sink with varying stiffness

2015 ◽  
Vol 23 (16) ◽  
pp. 2567-2577 ◽  
Author(s):  
Claude-Henri Lamarque ◽  
F Thouverez ◽  
B Rozier ◽  
Z Dimitrijevic
Keyword(s):  
Energy Transfer ◽  
Mechanical System ◽  
Degrees Of Freedom ◽  
Dynamical Behavior ◽  
Practical Investigations ◽  
Targeted Energy Transfer ◽  
Constant Stiffness ◽  
Non Linear ◽  
Energy Sink ◽  
Linear Mechanical System

The dynamical behavior of a non-linear mechanical system with two degrees of freedom (DOFs) during free and forced excitations is studied analytically and numerically. The non-linearity of the system is represented intentionally by a smooth non-linear simple function with periodically varying stiffness around a constant value for the sake of practical investigations. Analysis of the system leads to a method that could be used to design the non-linear energy sink (NES) so that the behavior of the system during relaxation and its strongly modulated response (SMR) could be improved versus the constant stiffness configuration.

Sound Transmission Through a Double-Wall Structure Coupled with Two Trapezoidal Acoustic Cavities

2016 ◽  
Vol 08 (08) ◽  
pp. 1650100 ◽  
Author(s):  
Haosen Yang ◽  
Hui Zheng ◽  
Xiang Xie
Keyword(s):  
Theoretical Model ◽  
Sandwich Panels ◽  
Sound Transmission ◽  
Sound Insulation ◽  
Wall Structure ◽  
Acoustic System ◽  
Acoustic Cavity ◽  
Acoustic Cavities ◽  
Insulation Performance ◽  
Double Wall

This paper aims at investigating the sound transmission mechanism of a flexibly-linked finite length double-wall structure. The problem stems from the modeling of sound transmission through corrugated core sandwich panels for predicting its transmission loss. The spatial segmentation of the acoustic gap and fully structure-acoustic coupling effect between the flexural vibration of the inclined mechanical link and the two adjacent trapezoidal acoustic cavities are considered. The theoretical model of the considered vibro-acoustic system is developed by using the modal superposition method in conjunction with envelope rectangular technique. Based on the developed theoretical model, the general vibro-acoustics characteristics of the system is presented. Particularly by using the [Formula: see text] mode of the acoustic cavity and the first structural modal frequency, the ratio between the aerostatic stiffness and the structural stiffness is formulated, and a criterion is proposed to determine whether the sound insulation performance of the vibro-acoustic system is controlled mainly by the structure or the acoustic cavity. Numerical investigations reveal that with different stiffness ratio, the acoustic cavity affects the sound transmission through both the added stiffness and added mass following different mechanisms. Besides, the influence of the inclined angle of the connecting beam on sound insulation performance of the double-wall structure is also studied. The obtained results are believed to be helpful in the optimal design of corrugated core sandwich panels for sound insulation.

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