Eventos Anais de eventos
COBEM 2021
26th International Congress of Mechanical Engineering
Differential evolution optimization of periodic micro-perforated chamber mufflers for low-frequency sound attenuation
Submission Author:
Adriano Goto , SP , Brazil
Co-Authors:
Adriano Goto, Jose Maria Campos dos Santos
Presenter: Adriano Goto
doi://10.26678/ABCM.COBEM2021.COB2021-1053
Abstract
Low-frequency noise is common as background noise in industrial and urban environments. Due to its properties of low acoustic dissipation and high propagation effectiveness, the control of this particular noise is a recurrent challenge in acoustic design. An interesting solution is the use of micro-perforated elements. The submillimetric dimensions of the holes provide a high acoustic resistance and a low acoustic reactance which enhance the sound attenuation at lower frequencies. For duct noise problems, the concept of micro-perforated elements can be used in conventional reactive-type silencers, such as chamber mufflers by inserting an internal micro-perforated duct. This setup, called micro-perforated chamber muffler (MPCM) also exhibits interesting phononic crystals (PCs) behavior when set periodically. The periodic arrangement provides the appearance of bandgap regions where the waves cannot propagate. Therefore, the acoustic performance of MPCM can be improved by combining the periodicity and the dissipation effects. For the present paper, the forced response, the transmission loss, and the dispersion diagram are evaluated for periodic MPCM systems by using an alternative transfer matrix approach. Numerical cases are computed and validated with the Finite Element method. The influence of geometric parameters is investigated and the differential evolution optimization is implemented in order to increase the acoustic performance for the low-frequency range. Simulated results show a considerable improvement of the sound attenuation at frequencies below 500Hz at feasible geometric dimensions.
Keywords
Micro-perforated duct, Chamber Muffler, Periodic Systems, Differential Evolution, Transfer Matrix Method
