Structure-acoustic Coupling Analysis And Vibration And Noise Reduction Effect Research Of Marine Gearbox

Gearbox is an important component used in large-scale mechanical equipments, and it’s performance has direct influnce on efficiency and reliability of mechanical equipments, the vibration and noise caused by high speed and heavy load gear transmission curbs the development of high-performance national defense equipments. Therefore, researches on vibration and noise reduction method are one of the most important duties in gearbox manufacturing.This paper is supported by National Natural Science Foundation of China, it takes marine gearbox which is under ahead condition as research object, and focuses on vibration and noise issues. Parameter identification of joints of marine gearbox, internal incentive mechanism simulation of gear pair, transmission error optimization, structure-acoustic coupling noise estimation, and researches on multi-frequency and multi-point noise optimization method were both carried out. The main research work in this paper can be summarized as follows:① The time-varying mesh stiffness had been obtained by ISO algorithm in LMS Motion modula, the mesh damping was calculated afterwards by using theoretical equation. Kinetic differential equation of the gear transmition sysytem was established by using lumped parameter method, dynamical stiffness matrix of the system was deduced, with the combination of the matrix of frequency response function obtained by experiment modal analysis, the bearing stiffness and bearing damping were calculated by least squares in Matlab, the simulational results fits the experimental data well, so it had verified the rationality of the identification method.② Static analysis model of the shaft system of the gearbox had been set up in Romax, the single tooth meshing stiffness and the transmission error were calculated and fitted to internal excitation. Dynamic response was performed by modal superposition method by using Ansys software. With the optimization of the transmission error by using genetic algorithm in Romax, the internal dynamic excitation had been reduced, so the vibration response of the gearbox had decreased effectively.③ The rigid-flexible coupling dynamic modal of the gear system were established in LMS/Motion modula, and then calcalated to obtain the bearing forces. Taking the bearing force as boudary condition of the structure-acoustic coupling field, the acoustic-structure coupling analysis model which contains structure mesh, acoustic mesh and field point mesh of the marine gearbox was established and solved to get the surface acoustic pressure and the radiation noise pressure in Acoustic modula. It had been verified the rationality of the structure-acoustic coupling method by comparing the simulational results and the experimental data.④ Taking the thickness of the gearbox as design variable, the mass of the gearbox as constraint condition, the minimum value of the pressure of multi-field point and multi-frequency band as object function, the acoustic optimization analysis modal had been set up in LMS/Optimization modula, design viriables were obtained by using the normal boundary intersection multi-objective optimization algorithm. The structure-acoustic coupling modal was recalculated after the rouding of the design viriables, the effect of the optimization was verified by comparing the data before and after optimization...