Research On Vibration And Acoustic Of Two-dimensional Periodically Distributed Bulk-damping

On the basis of one-dimensional periodic damping structure in our laboratory, thevibration and acoustic radiation characteristics of two-dimensional periodicallydistributed bulk-damping has been researched, and to verify the corresponding ofconclusions in practical engineering application, it has been applied in thelow-frequency vibration noise of actual vehicle case, these make the damping structureenriched, the passive noise reduction methods for interior vehicle noise improved.First, The theory model of two-dimensional periodically distributed bulk-dampingstructure is put forward in this paper, based on the theory of FEM, and Bloch periodicboundary conditions, the band frequency of single cell can be got.And then the bandfrequency diagram of each cell can be mapped.The effects of low frequency band gapwith lattice constant damping ratio and thickness of damping structure parameters isalso discussed in this paper.Secondly, the acoustic radiation of a specific plate based on two-dimensionalperiodically distributed bulk-damping structure is calculated by the FEM and BEMmethod,by comparing with the plate structure based on the whole free dampingstructure,the advantage of reducing the sound radiation of plate structure based ontwo-dimensional periodically distributed bulk-damping structure is verified.Then, aiming at a low-frequency noise problems of a class A car. First, find out themajor contribution lamella piece for low-frequency noise by using CAE simulation. Thesound pressure values near the ear of the car driver is chosen for reference, bycomparing the acoustic response of the car body-in-white based on two-dimensionalperiodically distributed bulk-damping structure and the whole free damping structure,the advantage of two-dimensional periodically distributed bulk-damping is verified,theoretical method reference for the actual vehicle noise reduction engineering would beprovidedLast, the acceleration transfer function and the sound pressure of a plate based ontwo-dimensional periodically distributed bulk-damping structure is tested by B&K toverify the previous relevant conclusions.