Applied Research Of Two-dimensioanal Periodic Damping Structure On Vibration And Noise Reduction Of Buildozers Cab

With the increasingly prosperous and fierce competition of engineering machinery market, the noise level of engineering machinery made more stringent requirements. Due to engineering mechanical of various vibration eventually will through frame passed to cab and outside noise through air media passed to cab. Therefore, the noise of engineering machinery cab is particularly large. Bulldozers cab General through using large damping to reduced cab noise, the limitation is damping material using rate low and economic cost high. This paper proposed the way of laying two-dimensional periodic damping, it can guarantee good vibration damping and noise reduction, at the same time,it can reduces the quantity of damping material and improves the efficiency of damping material.Firstly, introduces basic concept of acoustic, acoustic continuity, acoustic status, and acoustic motion equation. Given a two-dimensional periodic damping noise/sound radiation and Panel acoustic contribution calculation formula.Establishment simulation model of two-dimensional periodic damping sheet structure. Calculation of two-dimensional periodic structure modal,acoustic radiation characteristics, Sound Insulation characteristics. By comparison with laying block damping. The natural mode of the two dimensional periodic damping thin plate is larger than the large block damping. With the increase of frequency, this increasing trend is more and more obvious. Under the same laying area, two dimensional periodic damping structure is more able to restrain the vibration and have a better sound insulation effect. Further analysis the impact of the lattice constant, the density, stiffness, damping shape parameters on characteristics of two-dimensional periodic damping structure sound insulation and sound radiation.Then, taking a bulldozer’s cab as research objects. Establish cab car simulation model, In the HYPERMESH software, the pre-processing and grid division of the model are carried out. The cab structure, cab cavity and acoustic-structure finite element model are analyzed by modal. Discusses the basic vibration characteristics. Frequency response analysis of the driver’s ear are carried out. Research the driver’s ear position the basic Identify the main effect frequency of the driver’s ear sound field.Based on the shortcomings of traditional laying damping. By using the method of acoustic contribution, establish optimization process of the laying damping material in the cab, divide the area of Suitable for the laying of damping material. Through the calculation of the panel acoustic contribution. Get the positive and negative values of panel acoustic contribution. The values of acoustic panel contribution is positive and big which These areas are identified as laid damping material Laying 27.6%, 40.5% two periodic damping and 100% block damping for these panels. Simulation again, the results show: in the lower section 0-100 Hz, Full damping have more advantageous to reduce noise in the cab, in the frequency of 100-400 Hz and 600-900 Hz, laying 40.5% of two-dimensional periodic damping is more conducive to suppress the vibration of the cab. The sound pressure level curves of 40.5% two dimensional periodic damping and full damping in other frequency sections are not quite different. Verify application of two-dimensional periodic structure in the vehicle cab advantages. It provides a theoretical support for the vibration and noise reduction of cab actually.