| Vibration environment to satellite during launch was very harsh, which caused a satellite launch mission failed for damaged by vibrations within wide spectrum from all directions. It was difficult to achieve the purpose of reducing vibrations through changing the satellite structure because of complex structure of the satellite. But the rigid cone shell adapter which used to connect rocket and satellite was almost impossible to isolate vibrations from the rocket. Based on the actual need for urgent projects, research on the whole-spacecraft isolator technology increasingly emerged. Whole- spacecraft isolator usually means modifying the adapter’s structure, or adding a vibration-damping device interposed between the adapter and the satellite to achieving vibration isolation. Currently the whole-spacecraft isolator research focused on active vibration isolation technology, but active vibration isolation meant of low reliability, therefore passive vibration with more reliable could adapt to current needs of the whole satellite isolation. Based on passive vibration isolation technology, this paper presented a combination of the six degrees of freedom vibration isolation platform and cone shell adapter into a isolation solution.In view of the Stewart platform which acted as the core of this modular vibration isolation adapter, this paper established kinetic equation of the general configuration platform considering foundation excitation using Newton-Euler method to and simplified the equation according to micro-vibration characteristics between the satellite and the rocket interface. Then this paper selected a kind platform with symmetrical configuration and described its characteristic matrix using a group of parameters, then established parameterized dynamic model of the platform. Through establishment of a multi-body dynamics simulation model of vibration isolation platform in ADAMS software, it verified the correctness of theoretical modeling through modal and vibration response analysis. Thus the six degrees of freedom equation was decomposed into two degrees of freedom equations and two single degree of freedom equations which was independent each other according to the decoupling characteristic of the equation.According to vibration theory, the natural frequencies’ analytical solution was worked out. thus studies the design parameters on the natural frequency the impact of the law, summed up the general principles of the natural frequency of the platform design, so that the natural frequency of vibration isolation platform configurations can be designed to have a strong resistance, it is also given modular adapter using this scheme theory.This paper obtained all the transfer functions of the system in every directions by doing Laplace transform of all the equations. With these transfer functions, this paper studied the main platform design parameters’ effection on axial and lateral vibration transmissibility, and gave the general parametric design principle of transmissibility, so that transmissibility isolation platform configurations could be designed accurately.Established isolation adapter finite element model in the ABAQUS software, this paper did modal analysis and harmonic response analysis. Having got main modal information and the acceleration transmissibility curves, analysis and comparison with the theoretical model which under the assumption of rigid body was done, It summarized the laws of how the flexible structure impacted vibration isolation performance of the adapter, pointing out that the high-frequency local modes are important factors affecting the high-frequency transmissibility. What’ s more, this paper did modal analysis and harmonic response analysis by establishing cone shell adapter finite element model. It was found that the vibration isolation adapter had a good vibration isolation performance, which meant significantly broadening the vibration frequency band and effectively reduced the peak transmissibility(laterally reduced 6 d B, longitudinal reduced 13 d B). |
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