Study On Damping Properties Of Nonuniform Coatings Based On Density Differentiation

Vibration is a common phenomenon in life.Long-term service of the parts under vibration environment would produce stress concentration,fatigue damage and shorten its service life.Through the surface coatings technology can improve the damping performance,and wear resistance,corrosion resistance,fatigue resistance and other properties.The damping properties of traditional organic polymer damping materials are greatly weakened by the adverse environmental factors such as high temperature and high corrosion.Therefore,the damping properties of inorganic coatings with high temperature stability and excellent mechanical properties have been paid more attention.In this paper,through the design of coatings materials and coatings structure,the influence law of its microstructure on its damping performance was explored,and the damping mechanism was analyzed.The Mo-based coating was prepared by using supersonic arc spraying technology on the stainless steel substrate.The powder-cored wire was rolled and drawn from Al alloy strip coated with different components.The Mo-based coating was prepared by using supersonic arc spraying technology on the stainless steel substrates.The powder-cored wire was rolled and drawn from Al-Mg alloy strip coated with different components.The change rules of the loss factor and frequency,temperature and amplitude of the damping performance were explored.Different porosity were established by using finite element analysis software ABAQUS,Through modal analysis,the natural frequency of the system,the vibration forms and the stress nephogram of each mode of the system were determined.Through modal analysis,the natural frequency of the system,the vibration forms and the stress nephogram of each mode of the system were determined.The amplitude-frequency characteristic curves of the coatings system were obtained by harmonic response analysis,and the damping ratio was calculated by using half-power bandwidth method.The damping ratio of the coating was discussed.The main conclusions are as follows:Mo-based coating has a typical layered structure,and there were some defects in the coatings and the substrates.Adding Si C and polystyrene can improve the porosity of the coatings,and the porosity of adding polystyrene was greater than that of adding Si C.The maximum porosity of the CM4 coating with Si C and polystyrene was 0.248.The maximum porosity of the coating with Si C and polystyrene was 0.248.Mo-based coating exhibits good damping performance in three modes of frequency,temperature and amplitude,and frequency had the greatest influence on the damping performance of the coating.The damping performance of the coating at 150 Hz was much higher than that at 1 Hz.With the increase of the porosity and thickness of the coating,the damping property of the coating was enhanced.The CM4 coating with a porosity of 0.248 and a thickness of 300 ?m had the best damping performance and the loss factor could reach 0.054.The analysis of finite element software ABAQUS showed that with the increase of porosity,the natural frequency increase,the strain amplitude decreased,and the damping ratio increase.After being subjected to external excitation force,the maximum shape variable with coatings were less than those without coatings,which indicate that part of vibration energy was absorbed,thus increase the damping effect.Combined with the analysis of the DMA experimental results,the experimental results were basically consistent with the simulation results.With the increase of the porosity of the coatings,the damping ratio increase and the damping performance was enhanced.