Research On Vibration And Noise Control Method Of Gearbox Based On Phononic Crystal Characteristics

The vibration and noise of gearbox have always been one of the key problems to be solved in engineering.On the one hand,the vibration of the gearbox affects the overall operational performance of the equipment it is located in.Long term vibration can cause structural failure or damage,thereby reducing the safety and reliability of the equipment;On the other hand,the sound radiation generated by gearbox vibration can increase the noise in the working environment,affecting the comfort and physical health of workers.Effectively suppressing the vibration and noise of gearbox is an important means to improve product quality,enhance reliability,and extend service life,which helps to promote the application and development progress of modern equipment.At present,the commonly used vibration and noise reduction technologies for gearboxes can be divided into two categories: improving and optimizing the gearbox itself,and adding auxiliary structures such as vibration isolators and damping materials.After the production and molding of the gearbox,it is not easy to undergo structural changes,and the vibration and noise reduction structure is limited by additional mass and installation space,often unable to achieve good suppression of vibration and noise in the medium and low frequency range with limited dimensions.This thesis applies local resonance type phononic crystals to the vibration reduction and noise reduction of gearboxes,utilizing the bandgap characteristics of phononic crystals to suppress the propagation of vibration and noise waves in gearboxes.This provides a new idea and method for solving the problems of low-frequency vibration and noise in gearboxes below 1000 Hz.The main research work and conclusions of the paper are as follows:(1)Taking the marine planetary reducer as the research object,the vibration characteristics of the gear box are analyzed.First,the modal solution under the restraint state is carried out to obtain the natural frequency and mode shape within 1000 Hz before the box.Based on the mode superposition method,the vibration response of the box under simple harmonic excitation is calculated and analyzed.Vibration acceleration level curves of key measuring points in different areas of the box surface are extracted,and the main frequency of the box vibration is obtained.(2)Radiated noise analysis of the box is carried out based on acoustic finite element method.The radiated noise simulation model of gear box is established,which integrates the box structure grid,acoustic grid and field point grid.The radiated sound power curve of the box and the sound pressure level frequency domain curve of key monitoring points in the sound field are obtained.Based on the acoustic transmission vector method,the panel acoustic contribution of the box is analyzed to determine the subsequent noise reduction plates and frequency.(3)Based on the structural form of the gearbox box,two kinds of local resonant phononic crystal structures are proposed.Based on the elastic wave equation and Bloch theorem,the band structure of phononic crystal is solved and the mechanism of band gap generation is explored;The influence of geometric parameters and material parameters of phononic crystal structure on the band gap was investigated.The band gap was actively regulated by applying pre-stretching deformation to the phononic crystal structure;The vibration and acoustic radiation characteristics of phononic crystal plates with finite periodic arrangement are simulated,and the feasibility of applying them to vibration and noise reduction of gear box is analyzed.(4)Based on the surface structure of gear box,two types of locally resonant phonon crystal plates are proposed.According to the elastic wave equation and Bloch’s theorem,the band gap is solved and the generation mechanism of band gap is discussed.The influence of geometric parameters and material parameters on the local resonant band gap of Phonon Crystal structure is analyzed.The band gap is actively regulated by applying isometric pre-tension deformation to the Phonon Crystal structure.Vibration and sound radiation characteristics of phonon crystal structures arranged in finite period are simulated and the feasibility of applying them to vibration and noise reduction of gear box is analyzed.