Study On Modal Analysis And Acoustic-Structural Coupling Of The Muffler For Mining Truck

The noise pollution of heavy-duty mining trucks is serious,and the main noise source is from the exhaust noise of high-power diesel engines.Therefore,the control of exhaust noise is the most critical,and the most direct and effective way to control exhaust noise is to install exhaust mufflers.Based on the new split gas hedging principle,the research group has developed a new type of muffler with high efficiency noise reduction and low back pressure,starting from reducing the exhaust gas flow velocity.In this new type of muffler,its own vibration characteristics have an important impact on the performance of the muffler.Therefore,based on the principle of shunt gas hedging,this thesis studies the structure and performance of a new type of muffler for mining trucks,and studies the modal frequency and mode shape of the muffler for mining trucks by finite element numerical method and experimental method.On the basis of the above research,the finite element numerical method is used to analyze the acoustic-vibration coupling modal characteristics of the muffler for mining trucks,including the coupled modal frequency and the coupled modal shape.The result shows:(1)Within 0-500 Hz,the modal shapes corresponding to the 7th and 8th order modes show obvious internal structural vibration,and their characteristic frequencies are low and the phenomenon of multiple root modes appears.The acoustic modal analysis was carried out in the air domain inside the muffler of the mining truck,and the modal frequencies and mode shapes that may be coupled with the structural modes in the range of 0-500 Hz were analyzed.(2)In the modal analysis of the mining truck muffler test,the elastic modal frequencies and modal shapes in the range of 0-500 Hz to the 8th order were searched,and the MAC matrix verification of the modal shapes was carried out at the same time.There are high independence between each mode shape and high consistency between the same mode shape.(3)The coupling mode of the new type of muffler for mining vehicles,which takes into account the effect of acoustic-vibration coupling,is obtained,and the 17-order system modal parameters in the frequency range of 0-500 Hz are obtained.Based on the test modal results,the error rates of the coupled modal and the single structural modal considering the acoustic-vibration coupling effect are 4.798% and 5.2%,respectively.The results show that the coupled modal analysis considering the acoustic-vibration coupling effect is closer to reality.The research results have provided a theoretical support for the design and application of a new type of exhaust muffler for mining trucks based on the principle of split-stream rushing muffler.