Experimental Validation of Vibro-Acoustic Modeling of Automotive Mufflers and Transmission Covers 2003-26-0036
A reactive type of muffler of a 4-stroke Auto-Rickshaw was modeled using a commercially available Acoustic Finite Element Analysis (FEA) software like Sysnoise. Design sensitivity of different geometry parameters of mufflers to its Insertion Loss over a wide frequency range was studied. The analytical results were validated by the Laboratory Speaker test. But in the presence of a hot gas flow, the Insertion Loss characteristics of the muffler were far different. As the flow speed increased, negative attenuation was found in some frequency bands.
The second part of the paper studies the software prediction of structure borne noise from a transmission cover of a Motorcycle. The sound power level was predicted by uncoupled fluid-structure analysis of Boundary Element Method (BEM). To reduce the sound power radiated from its top surface, a ribbed pattern and increase in thickness were proposed. The software output regarding the sound radiation efficiency of the cover was only partly validated.