Friction Energy Dissipation Method For The Noise Reduction Of Cmg Rotor System And Experimental Study

Control Moment Gyro(CMG)is the important component of directional control system on spacecraft,but the noise caused by non-linear excitation has an unfavorable effect on the stable running of the equipment.The vibration and noise is transmitted as wave in the structure,and there is a certain position difference between the crest and trough.The friction energy dissipation method is often applied in the study of structural vibration and noise reduction for its simple and efficient characteristics.Therefore,according to the amplitude and phase characteristics of the vibrating rotor,the paper presents a kind of mosaic structure with friction damping to reduce high frequency noise.Aslo,researches of the friction energy dissipation method are carried on in this paper.The acoustic analysis of the CMG rotor,including the surface acoustic pressure and the radiated sound pressure,shows that there appear concentrated areas of the noise energy below 10000 Hz,and with the increase of the frequency,the distribution difference will become less obvious.According to the analysis of rotor’s plate contribution,an obvious result is that rotor rim contributes the most noise.The directional analysis shows that noise is concentrated in the region where the included angle is 60 degrees down from the axis.The shape of vibration structure is just like a waveness.Based on the modal superposition method,the friction energy dissipation structure of the CMG rotor system is designed.According to the characteristics of the true displacement vector,the rotor rim is divided by statistical method,and the smaller amplitude region is found between regions with inverse directions of vibration,for the friction energy dissipation device inlay installation.The rationality of the selected location is verified by analyzing with different evaluation indexes.On this basis,the design of friction energy dissipation structure of CMG rotor system is carried out.The inherent vibration characteristics of friction dampers with different structural parameters are analyzed,and it is found that with the increase of opening angle and opening width,the friction damper has more modes under 20000 Hz,and its natural frequency is shifted to low-frequency range.Moreover,based on the simulation of the friction damper’s energy dissipation characteristics with a 3-D micro-slipping friction modal,such a conclusion can be drawn that the relative energy dissipation capacity of the rotor increases with the increase of the initial stress and the damper’s opening size.According to the results of previous simulation,friction dampers can be designed with difference parameters,including initial pressure,opening angle.Through experiments,it is found that the application of the damper has a favorable effect on the high-frequency noise in the rotor system.