A statistical design optimization study of a multi-chamber reactive type silencer using simplex centroid mixture design

Erkan Seçgin,Hakan Arslan,Burak Birgören

doi:10.1177/1461348419901227

Abstract

This study aims to optimize the acoustic performance of a silencer with baffles having extension tubes. It considers the position, the number and the extension geometry of the baffles as design variables and sound transmission loss as the response variable to be optimized. The finite element analysis software ABAQUS is used to compute the response values for different combinations of design variables. The statistical design of the experiments provides a mathematical framework for such computer design optimization studies with multiple design variables. Yet, it has not been used for design optimization of silencers in the literature. In this study, simplex centroid mixture designs, a type of response surface method, are used in the statistical design of experiments. They can provide faster convergence on the optimization problem. The design involves one, two and three baffles with different positions and extension tube lengths. The outcome of this study indicates that obtaining ABAQUS software solutions at design points for each baffle number allows constructing nonlinear regression equations expressing the response variable as a function of the design variables. The equations obtained are then used to compute optimal values. Further evaluation of these equations indicates that better sound transmission loss values are obtained when the baffle number is increased, and the lengths of the extension tubes are set at high values. Moreover, it is possible to use the statistical experimental design approach implemented in this study for other types of silencers with different baffle geometries and design variables.

Highlights

Studies on sound reduction always attract the attention of researchers due to the negative effects of sound and noise on human health
Investigation of the silencer performance with and without extension tubes In order to compare the performances of silencers with and without extension tubes, initial values are assigned to the parameters in Figure 3 based on past experience; the values are given in the first column of Table 2
The FEA results of silencers having one baffle with and without extension tubes are given in Figures 9 and 10, respectively

Summary

Introduction

Studies on sound reduction always attract the attention of researchers due to the negative effects of sound and noise on human health. Silencers are equipment used to reduce the volume of sound and noise. They reduce the sound pressure generated by sound-generating sources such as motors, fans, weapons by using intertwined perforated pipes, expansion chambers or various sound insulation materials.[1]. Silencers are generally classified as reactive, dissipative and hybrid type according to designs and requirements. Reactive silencers generate dissipative sound waves caused by geometric discontinuity by means of acoustic impedance difference. Dissipative silencers transform sound energy to heat energy and decrease acoustic pressure fluctuations. Hybrid silencers are composed of reactive and dissipative silencers. The selection of the silencer type and the internal design depends on the frequency band of the sound and conditions of use.

Objectives

Methods

Results

Conclusion