Numerical analysis and design of dissipative mufflers by the finite element method

The development of a technique for designing noise mufflers with desired characteristics is an important and urgent problem. Having been developed, it will increase the efficiency of the designed acoustic mufflers, which, in turn, will reduce the noise of vehicles and thus contribute to solving the problem of noise pollution of the environment. However, since such technique has not been developed yet, the creation of mufflers and finding its acceptable configuration is a time consuming work. The paper proposes a method for choosing the configuration of dissipative noise mufflers under constraints imposed on their overall dimensions. The proposed approach implies introducing an integrated acoustic efficiency index (generalized OTL) for a muffler prototype with dimensionless parameters. The study was conducted numerically using the finite element method. The finite element model of the dissipative muffler uses acoustic characteristics of a fiber sound-absorbing material, which are measured experimentally. Having specified initial data and using the proposed nomographic charts, the designer can find geometrical parameters of the muffler corresponding to the required acoustic efficiency indices within a predetermined frequency band with a minimum muffler volume and thus solve the optimization problem. The developed method will significantly reduce the time required for designing mufflers of vehicles.

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