Analysis of Sound Transmission Loss of Double-Leaf Walls in the Low-Frequency Range Using the Finite 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.

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

Noise Control Engineering Journal ◽

10.3397/1/376831 ◽

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.

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