Sound transmission modeling and numerical analysis for automotive seal considering non-uniform compression

2018 ◽  
Vol 233 (3) ◽  
pp. 471-483 ◽  
Author(s):  
W-F Zhu ◽  
Y Zhong ◽  
G-L Wang ◽  
X-H Jiang
Keyword(s):  
Numerical Analysis ◽  
Transmission Loss ◽  
Sound Transmission ◽  
Transmission Model ◽  
Geometrical Parameters ◽  
Sound Transmission Loss ◽  
Uniform Compression ◽  
Metal Seal ◽  
Wide Range ◽  
Transmission Modeling

Automotive metal door panels and nonmetallic seals have complicated nonlinear interactions in their narrow mating sections, leading to non-uniform compression and complicating the sound transmission mechanism. Therefore, a new sound transmission modeling methodology and numerical analysis is developed for a refined sealing system by considering the geometrical boundaries and the non-uniform compression load. Nonlinear analysis is performed to obtain the geometrical parameters of the deformed seal, which are later input to the subsequent numerical acoustic model, by varying the compression ratios at different door locations under quantified nonlinear metal–seal interaction boundary conditions. A numerical prediction model of the sound transmission loss is constructed considering the deformed seal geometry using a double-wall-panel sound transmission model. Finite-element analysis and an infinite-element method are combined. Sound transmission loss experiments are conducted by varying the compression ratios of the seal. Experimental results are in good agreement with the numerical analysis. Furthermore, the sound transmission loss of the incident sound source with respect to a wide range of frequencies is numerically predicted for different compression magnitudes and directions using the verified methodology. This shows that the presented model and numerical methodology is valuable for optimizing the sound transmission loss performance of automotive door seals.

Excellent low-frequency sound absorption of radial membrane acoustic metamaterial

2017 ◽  
Vol 31 (03) ◽  
pp. 1750011 ◽  
Author(s):  
Nansha Gao ◽  
Jiu Hui Wu ◽  
Hong Hou ◽  
Lie Yu
Keyword(s):  
Transmission Loss ◽  
Low Frequency ◽  
Sound Transmission ◽  
Ring Structure ◽  
Circular Ring ◽  
Effective Density ◽  
Geometrical Parameters ◽  
Membrane Thickness ◽  
Sound Transmission Loss ◽  
Acoustic Metamaterial

This paper proposes a new radial membrane acoustic metamaterial (RMAM) structure, wherein a layer membrane substrate is covered with a rigid ring (polymethyl methacrylate frame and aluminum lump). The dispersion relationships, transmission spectra and displacement fields of the eigenmodes of this radial membrane acoustic metamaterial are studied with FEM. In contrast to the traditional radial phononic crystals (RPCs), the proposed structures can open bandgaps (BGs) in lower frequency range (0–300 Hz). Simulation results show that the physical mechanism behind the bandgaps is the coupling effects between the rotational vibration of aluminum lump and the transverse vibration of membrane. Geometrical parameters which can adjust the bandgaps’ widths or positions are analyzed. Finally, we investigate the axial sound transmission loss of this acoustic metamaterial structure, and discuss the effects of factor loss, membrane thickness and the number of layers of unit cell on the axial sound transmission loss. Dynamic effective density proves the accuracy of the FEM results. This kind of structure has potential application in pipe or circular ring structure for damping/noise reduction.

scholarly journals Analyzing and evaluation of effective parameters on sound transmission loss of the triple-layered acoustic panels with sound-absorbing middle layer

2015 ◽  
Vol 4 (2) ◽  
pp. 250
Author(s):  
Nader Mohammadi
Keyword(s):  
Boundary Condition ◽  
Porous Material ◽  
Elastic Layer ◽  
Transmission Loss ◽  
Sound Transmission ◽  
Air Gap ◽  
Acoustic Properties ◽  
Sound Transmission Loss ◽  
Static Young’S Modulus ◽  
Wide Range

In this research, a triple-layered acoustic panel with sound-absorbing intermediate layer materials is modeled analytically in order to calculate the sound transmission loss in the normal incidence field. This information provides an appropriate platform for optimum noise control. In this paper, porous material is used as an absorbent layer between two elastic panels. In modeling these triple-layered panels, theory of wave propagation in porous materials is used and bounded boundary condition of the first elastic layer and unbounded boundary condition of the second elastic layer is applied. To validate the model, the results of this model are compared with the results of the Bolton. Comparison of results revealed very good compatibility. Here, the effect of the length of the air gap between the elastic layers, density and the material of the elastic plate, the thickness and vibro-acoustic properties of the intermediate porous material on the values of transmission loss is investigated.In a wide range of frequencies, increasing air gap, density of elastic panels and porous layer thickness, increase the transmission loss up to 10 dB. At frequencies above 10 kHz, a reduction in porosity, static Young's modulus, the loss coefficient, increasing bulk density of the solid phase, the factor of geometrical structure and viscosity of porous material, increase the sound transmission loss up to 15 dB.

scholarly journals Tuning acoustic performance of multi-chamber hybrid mufflers

2021 ◽  
Author(s):  
Van-Hai Trinh
Keyword(s):  
Transmission Loss ◽  
Sound Transmission ◽  
Numerical Approach ◽  
Geometrical Parameters ◽  
Sound Transmission Loss ◽  
Expansion Chamber ◽  
Low Frequencies ◽  
Acoustic Performance ◽  
Chamber Length ◽  
Perforated Tube

In this paper, we investigate the functional acoustic performance of multi-chamber mufflers using a numerical approach. The wave propagation governing in expansion chamber domains is first introduced and solved by the finite element method. Our numerical results of selected muffler configurations are compared with the reference predictions model and experiments in order to validate the present procedure. Then, the influence of the geometry characteristics of typical and hybrid configurations of multi-chambered mufflers (number of sub-chambers, micro-perforated tube structure) on their sound transmission loss is studied. The obtained results indicate that the structure of the considered muffler has a strong effect on their acoustical performance, and the location and the high level of resonances of the sound transmission loss behavior are strongly related to the number of sub-chambers as well as micro-perforated tube characteristics. By tuning geometrical parameters (e.g., having a small perforation ratio), we enable to design mufflers having a higher sound transmission loss (up to 110 dB) at low frequencies (~ 195 Hz) but a constraint space (e.g., acoustic chamber length of 300 mm).

A numerical study on the sound transmission loss of HST aluminum extruded panel

2020 ◽  
Vol 68 (5) ◽  
pp. 367-377
Author(s):  
Xu Zheng ◽  
Peilin Ruan ◽  
Le Luo ◽  
Yi Qiu ◽  
Zhiyong Hao
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Performance Optimization ◽  
High Speed ◽  
Transmission Loss ◽  
Numerical Study ◽  
Sound Transmission ◽  
Sound Transmission Loss ◽  
Wide Range ◽  
Element Method

Aluminum is a light, strong, and corrosion-resistant material. Its extruded form, the aluminum extruded panel, consists of two aluminum plates with truss core, which can be applied in a wide range of engineering areas. In this work, the structure-acoustic coupling finite element method (FEM) is employed to analyze the sound transmission through high-speed train (HST) aluminum extruded panels. The automatically matched layer (AML) is used to simulate the non-reflective boundary condition. It is found that the predicted sound transmission loss (STL) is in good agreement with the experimental results and the prediction accuracy of the finite element method can be further verified. Based on this proposed method, a parametric study is carried out to investigate how the structure parameters affect the STL. The results suggest that the rib angle exhibits a greater effect on STL in the above-middle frequency area where the modal density is high. The increase in the height between the panels will lead to a higher STL overall value of the aluminum extruded panel and make the STL dips move toward higher frequencies, while the increase of the rib thickness will drive the STL dips to an opposite direction. Finally, the STLs of the aluminum extruded panel in different regions of the train body are comprehensively analyzed. The highest overall value of STL is found in the flat-top region, whereas the lowest value appears in the curve-top region. Overall, the results in this article can provide valuable implications for the noise performance optimization of HST.

Optimization of Sound Transmission Loss Characteristics of Orthogonally Stiffened Plate

2018 ◽  
Vol 26 (04) ◽  
pp. 1850010 ◽  
Author(s):  
Tao Fu ◽  
Zhaobo Chen ◽  
Hongyin Yu ◽  
Chengfei Li ◽  
Xiaoxiang Liu
Keyword(s):  
Transmission Loss ◽  
Structural Parameters ◽  
Sound Transmission ◽  
Stiffened Plates ◽  
Geometrical Parameters ◽  
Sound Transmission Loss ◽  
Stiffened Plate ◽  
Acoustic Performance ◽  
Theoretical Predictions ◽  
Field Excitation

An analytical model is developed to investigate the sound transmission loss from orthogonally rib-stiffened plate structure under diffuse acoustic field excitation. The validity and feasibility of the model are verified by comparing the present theoretical predictions with the numerical results published previously. The influences of structure geometrical parameters on sound transmission loss are subsequently presented. The optimization algorithm is used to search for the optimal structural parameters with the objective to maximize the sound transmission loss over a frequency band. Furthermore, the sensitivity of structural parameters on the overall vibration and acoustic performance of the stiffened plates structure is also analyzed.

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