Analysis And Research On Vibration And Noise Of Compartment Of A Fire Engine Structure

According to the noise problem of a type of forest fire engine,the noise of vehicle body structure has been researched based on acoustic direct boundary element method.The finite element model and the sound field boundary element model are established,The free vibration modes of the white body and the vibration acceleration of the vehicle mounting points under idle conditions are tested.The reliability of white body model is verified by testing modal,The frequency response analysis is carried out by taking the vibration acceleration of the mounting point as the model boundary condition.The body frequency response data is mapped to the acoustic boundary element mesh as boundary condition in LMS Virtual.Lab acoustic plate.Sound pressure level at field point is calculated between 20Hz-200Hz.139Hz is found to be the frequency corresponding to the peak sound pressure.The noise of the last platoon occupant On the copilot side reached 53.17dB(A).The corresponding frequency of the peak sound pressure level of is found.The body is divided into 24 plates according to the angle.The contribution of body plate is calculated according to the frequency of attention.The ceiling and the front and rear floors were found to contribute significantly at all frequencies.An improved scheme is proposed to increase the thickness and the damping layer of the target plate.Peak sound pressure levels are effectively reduced by the two methods.It is considered that adding damping layer is a feasible method.The method of adding damping layer to field peak sound pressure level decreased by 3.29%.