The Design And Optimization For Damping Vibration Attenuation Of Marine Gearbox

The high speed, highly efficiency and brute force will be the final aim of the marine gearbox with the high development of the modern industrial technologies. Vibration and noise of the marine gearboxes have become a paramount problem. The vibration and noise affect the hiding of the ship craft and the stability of the transmission system, but also the crew's working environment especially when they are used for the marine gearbox in the modern ship craft. Therefore, it has great practical application values to the research on the vibration and noise of the marine gearbox. There are several ways to control the structural vibration. Damping vibration attenuation is an effective method to suppress the resonance. Three aspects of viscoelastic damping sandwich plate were analyzed based on the finite element method, such as materials'capability, loss factor and optimum thickness. Then the theory of the design and optimization of damping vibration attenuation is established, which provide theoretical basis for the design and optimization of damping vibration attenuation of the marine gearbox.It is always a difficult problem to model the viscoelastic damping material accurately in a dynamics analysis because frequency has great influences to characters of the viscoelastic damping materials. Dynamic analysis of sandwich structure with viscoelastic layer is carried out based on finite element method. Resonance frequency and structural loss factor are obtained and contrasted with theoretical value. Therefore, the correctness of the calculation method of structural loss factor is verified. The dynamics analysis of sandwich structure with viscoelastic layer would provide data support for following analysis and research.The parameter fitting formula between the damping structure parameters and structural loss factors is established by using nonlinear parameter fitting analysis based on the theory of generalized regression neural network. The optimization method is proposed based on the parameter fitting formula. Multi-objective optimization of constrained damping structure was carried out to determine the optimum thickness of damping layer and constrained layer. Then the parameter fitting formulas of damping layer and constrained layer's optimum thickness are established with different structural parameter. Finally the theoretical formulas of damping layer and constrained layer's optimum thickness were established based on the parameter fitting formulas. It provides theoretical basis for the practical engineering application of damping vibration attenuation.The finite element model of gearbox is established based on finite element method. Based on the modal analysis of gearbox, the position and optimum thickness of additional damping treatment are respectively determined according to structural modes and computing formula of damping structure. Then, the thickness and position of additional damping treatment are finally determined with size optimization and topology optimization of the traditional damping gearbox. Finally, the dynamic analysis of gearbox and damping gearbox are carried out respectively. The effect of damping vibration attenuation is analyzed based on the dynamic analysis results.