Research On The Characteristics Of Vibration And Acoustic Radiation Of Stiffened Plate Structure

In the driving process of high-speed train, the complex external excitation applied on the train will produce a lot of noise pollution, especially of locomotive cab noise, it will directly affect the driver’s working condition and even become a threat to the traffic safety. The structure causing the interior noise of train is mainly train skin stiffened plate structure. In this paper, the train stiffened plate was sat as the object of study and researching on the vibration and acoustic radiation characteristics of the flat plate, analyzing the acoustic radiation modes and structural modes and their radiation efficiency in terms of flat plate. By calculating the vibration and acoustic radiation characteristics of stiffened plate under different conditions, the structure of stiffened plate is optimized. The optimization scheme is verified by experiment.On the basis of the analysis of classical thin plate theory, the modal shapes of simply supported rectangular thin plate under the condition of simply supported and clamped edges are calculated. The acoustic radiation model of simply supported thin plate is established, and the calculating formulas of sound pressure, sound power and radiation efficiency are introduced. The vibration theory model of stiffened plate structure is established.Based on the theoretical derivation of the acoustic radiation modes of a simply supported plate, the acoustic radiation modes at different frequencies are obtained, which represent the distribution of the vibration velocity of the surface of the structure. The analytic solution of the radiation efficiency of the acoustic radiation mode and the structural mode is calculated. It is found that the radiation efficiency of the acoustic radiation mode is independent, and the radiation efficiency is the coupling.The exact value of the sound power of the thin plate under different excitation points and different materials was analyzed, and the simulation results were compared with that of the finite element software Virtual.Lab. The vibration velocity and the radiation efficiency of simply supported plate are calculated under different conditions using virtual. Lab. Analysis results show that excitation position on vibration and sound radiation effect is not obvious, the steel sheet to more significant than aluminum effect of reducing vibration and noise, boundary condition and its influence on the vibration is not obvious, and the radiation efficiency clamped to greater than simply supported.Stiffened plate model of the unit type is determined according to the actual situation, using the HyperMesh and Vitual.Lab established stiffened plate model under various conditions,simulated and calculated stiffened plate under external excitation vibration and sound radiation characteristics, calculated each plate block and acoustic power sector contribution amount under different working conditions of the rib plate and made the greatest contribution to the amount of the plate are obtained. Through the experimental verification of the sound insulation, the composite structure is better than the orthogonal model.