Finite element analysis of transversal modes and acoustic attenuation characteristics of perforated tube silencers

2012 ◽  
Vol 60 (3) ◽  
pp. 340-349 ◽  
Author(s):  
Z. Fang ◽  
Z.L. Ji
2019 ◽  
Vol 38 (2) ◽  
pp. 415-426 ◽  
Author(s):  
Jun Fu ◽  
Minghui Xu ◽  
Zengfeng Zhang ◽  
Wenjie Kang ◽  
Yong He

Aiming to obtain the acoustic attenuation performance of exhaust muffler of diesel engine and the influence of main structural parameters on its acoustic attenuation characteristics, the finite element analysis method and acoustic theory were adopted to numerically investigate the acoustic attenuation performance under the boundary condition of acoustic adiabatic propagation and muffler wall. It suggested that the noise cancellation effect of muffler was poor at the middle and low frequency in range of 0–3000 Hz, and the transfer loss of muffler was basically 0 dB pass frequency at 1100 Hz. According to previous single-factor study experience, the structural factors, such as the expansion ratio, insertion length of outlet perforated pipe, the distance between the diaphragm and the front part of muffler, have influences on the acoustic performance of muffler at low frequency. Thus, they were taken as the starting point to study the influence of multiple interaction factors on the muffling performance by using orthogonal design method combined with the finite element analysis method. The influence degree of different structure parameters on the acoustic performance of muffler and the optimized structure parameters were obtained. Through the analysis on the acoustic characteristic of the optimized muffler, it indicated that the transmission loss of the improved muffler had significant increase in other frequency range except the range of 650–800 Hz and 2500–2700 Hz, especially at frequency of 1100 Hz compared with the original muffler. In the range of 0–3000 Hz, the mean of transmission loss of the improved muffler was about 9.8 dB larger than that of original muffler, which indicated that better noise cancellation effect was achieved. The improved muffler also provided a certain reference for the structural improvement of similar muffler.


2011 ◽  
Vol 354-355 ◽  
pp. 535-540
Author(s):  
Jian Hua Xiang ◽  
Ri Dong Liao

The criterions of parameter selection for a tuned frequency muffler are proposed. The experimental results show that the radius of a cylindrical perforated tube dissipative muffler meets the criterions. Based on the conclusion, through installing the rotatable circumferential separate plates, an actuator of the tuned frequency muffler is designed to realize automatic adjustment of the radius, which is available for two kinds of working conditions of acoustic attenuation and can both attain the optimal acoustic attenuation performance. Utilizing the finite element analysis and the experiment test, variation rules of transmission loss versus the muffler’s radius is further investigated. The results show that the variable-radius method used in the tuned frequency muffler can shift the frequency band of acoustic attenuation and optimize the acoustic attenuation performance, which expands the application fields of mufflers and has a great engineering value.


2002 ◽  
Vol 11 (1) ◽  
pp. 30-40 ◽  
Author(s):  
Chatchai Kunavisarut ◽  
Lisa A. Lang ◽  
Brian R. Stoner ◽  
David A. Felton

2019 ◽  
Vol 13 (3) ◽  
pp. 5242-5258
Author(s):  
R. Ravivarman ◽  
K. Palaniradja ◽  
R. Prabhu Sekar

As lined, higher transmission ratio drives system will have uneven stresses in the root region of the pinion and wheel. To enrich this agility of uneven stresses in normal-contact ratio (NCR) gearing system, an enhanced system is desirable to be industrialized. To attain this objective, it is proposed to put on the idea of modifying the correction factor in such a manner that the bending strength of the gearing system is improved. In this work, the correction factor is modified in such a way that the stress in the root region is equalized between the pinion and wheel. This equalization of stresses is carried out by providing a correction factor in three circumstances: in pinion; wheel and both the pinion and the wheel. Henceforth performances of this S+, S0 and S- drives are evaluated in finite element analysis (FEA) and compared for balanced root stresses in parallel shaft spur gearing systems. It is seen that the outcomes gained from the modified drive have enhanced performance than the standard drive.


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