Study On Acousto-structural Coupling Characteristics Of The Cabin With Engine

Noise levels are an important indicator of the comfort evaluating vehicle, the engine noise of the car body structure vibration excitation force is an important source of motivation. Engine excitation force is transmitted through the passenger cabin to cabin sound field, there will be acoustic coupling phenomenon. Especially for the crew cabin of this thin-walled structure, the coupling effect is obvious. Mechanism of acoustic coupling, can increase the accuracy of forecasts and reduce the noise to give provide design basis. Finite element method is an effective way to solve the problem of acoustic coupling. In this paper, using the finite element method, Acoustic Boundary Conditions acoustic coupling system to establish acoustic coupling equation. Then coupled equations modal analysis and frequency response analysis and verify the correctness of the numerical algorithm. Then use simulation methods for vibro-acoustic coupling system model is studied. Through the study of the modal model, we found structural characteristic frequency, and frequency characteristics of the acoustic coupling relationship characteristic frequency, find the control board and frequency characteristics of the cavity frequency control characteristics. Offset for the structural characteristics and frequency characteristics of the acoustic frequency is analyzed, was found in the engine compartment acoustic coupling systems, low-level structural features common frequency offset smaller, low-level acoustic characteristics of the frequency offset generally increases. In frequency response analysis, the effects of the engine excitation force by four connection points on the crew cabin and internal structural vibration response of the sound field response. By harmonic response analysis, the study of the same amplitude harmonic excitation force, affecting four transmission paths to the crew cabin acoustic response of a particular field point; in response to the engine by calculating the excitation force were entered in the four connection points, the analysis engine excitation force the crew cabin acoustic response specific field point contribution in the amount of four connection points.