Sound Transmission Loss Analysis of an Automotive Dash by Finite Element Method

2003 ◽  
Author(s):  
Kin. L. Hong ◽  
S. T. Raveendra
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Transmission Loss ◽  
Sound Transmission ◽  
Sound Transmission Loss ◽  
Loss Analysis ◽  
Element Method

Optimization of sound transmission loss of open acoustic barriers with respect to unit cell topology

2021 ◽  
pp. 095440622199157
Author(s):  
Nan Li ◽  
Mabrouk Ben Tahar ◽  
Fusheng Sui
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Power Transmission ◽  
Transmission Loss ◽  
Design Method ◽  
Sound Transmission ◽  
Unit Cell ◽  
Sound Transmission Loss ◽  
Power Transmission Coefficient ◽  
Element Method

Open acoustic barriers exhibit excellent sound transmission reduction property at a certain frequency/frequencies which highly depends on the configuration of its unit cell. Design of unit cell configuration for minimum sound transmission at predefined objective frequency remains an open question. This paper aims at providing an automatic design method for open acoustic barriers with multi-material unit cell. Firstly, a wave finite element method is developed to calculate the sound transmission through an infinite array of periodic scatterers. As the unit cell contains infinite fluid domain, the application of Floquet-Bloch theorem to the boundaries of perfectly match layers (PML) is necessary and has been resolved in this paper. This wave finite element method with the implementation of PML is validated by comparing to analytical solution of sound transmission through an array of steel cylinders. Then a genetic algorithm is employed to optimize the sound transmission loss with respect to material distribution of a bi-material unit cell. Finally, the effectiveness of this inverse design is demonstrated by examples with different predefined frequencies. Corresponding unit cell typologies are obtained and the dips of sound power transmission coefficient curve are successfully tuned to objective frequencies.

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.

Vibro-acoustic and sound transmission loss analysis of truncated conical shell subjected to incident sound wave

2018 ◽  
Vol 25 (2) ◽  
pp. 435-444 ◽  
Author(s):  
Afshin Tebyanian ◽  
Mohammad Reza Ghazavi
Keyword(s):  
Acoustic Pressure ◽  
Transmission Loss ◽  
Outer Space ◽  
Sound Transmission ◽  
Acoustic Energy ◽  
Sound Transmission Loss ◽  
Loss Analysis ◽  
The Media ◽  
Shell Vibration ◽  
Element Method

A combination of analytical method for shell vibration, boundary element method (BEM) for acoustic media of shell outer space, and finite element method (FEM) for shell inner space was used to study the vibro-acoustic behavior and extract sound transmission loss factor (STL) of a coupled vibro-acoustic system. The equation of motion of the shell is extracted based on the Donnell–Mushtari hypothesis and using Hamilton principles. The acoustic pressure on the outer and inner space is obtained using BEM on the defined nodes on the surface and these localized nodal pressures are converted to nodal concentrated forces. Finally, vibration of the coupled vibro-acoustic model is solved in frequency domain and vibration response of shell and acoustic pressure at any point in the media (outer, on the surface, and inner of shell) are obtained. Also, the STL of the shell is extracted based on the ratio of total acoustic energy received by the shell to that transferred to inner space.

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