Research On Noise Radiation Characteristics And Techniques For Noise Reduction By Damping The Vibration Of The Fuselage Skin In The Course Of Riveting

Against the problem that loud strong radiation noise oriented from riveting in assembling aircraft seriously damages the hearing system of assembler, and impacts the assembly quality and efficiency , this paper studies the mechanism of noise making in fuselage skin riveting, the characteristics of radiation and the method to reduce vibration and noise by imposing damping, which focuses on using numerical calculation method to simulate the impact on vibration response and noise of different loading ways, and the effect of reducing vibration and noise by imposing damping, as well as discussing measures to improve the efficiency of reducing vibration and noise by setting optimized damping parameters.Firstly, the paper studies the mechanism of noise making in fuselage skin riveting and characteristics of radiation. The vibration response of sheet in the process of pressing rivet is a transient response process under wide-amplitude and short-time impulsive force, in which there are working noise made by rivet gun driven by cold air, bumping noise from collision of riveting head and rivet, and radiation noise in structural vibration activated by rivet head, etc. This essay only researches structural vibration radiation noise and the method to reduce vibration and noise by imposing damping. It mainly adopts finite element and boundary element method, establishes the feature calculation model of vibration displacement response and structural acoustic radiation under the impact of buffet load of plate and bracket, and obtains the vibration displacement of node, natural frequency and spectrum density of vibration response displacement, as well as the sound power of radiation noise and sound pressure level of any point of space. It also discusses in detail the impact on vibration noise with different boundary, different load and different action point. On this base, It establishes calculation and analysis model of dynamic character and response by imposing free damping layer in the veneer, uses numerical simulation method to calculate the structural vibration displacement response and sound power after imposing damping, analyzes and summarizes the impact on structural vibration displacement response and radiation noise of different damping parameters. In a word, the structural vibration radiation noise under the impact of buffet load in the process of skin riveting in making aircraft, numerical simulation method using damping to reduce vibration and noise, the calculated results and analysis conclusions in this paper have a certain reference and application value in advancing technics and equipment using damping to reduce vibration and noise, and improving assembly quality and efficiency.