Structural Analysis And Research On Unlockin Support Of High-resolution Space Camera

Spacecraft need a variety of connection-release devices to achieve space connection and unlocking function. These devices do not only guarantee reliable connection of the structures in process of launching, but also reliable unlocking and separation after injection.Clamp-band structure has a wide range of applications in aerospace engineering, and mainly are used in the satellite-rocket connection and separation. For a certain large off-axis three mirror anastigmatic(TMA) space camera, a device called clamp-band unlocking support is used to realize connection and release between the camera and satellite platform. Unlocking supports work in the launch stage of the satellite,so the dynamics environment is severe, and the release shocks on the camera equipment when supports unlock can not be ignored. So the clamp-band structure have significant influences on the dynamics characteristics of spacecraft, which must be given enough consideration to when partial or entire modeling is taken. At present, the domestic and international researches about the clamp-band structure is still not perfect. This article studies the structure in-depth through finite element analysis(FEA), direct modeling, test and shock response spectrum(SRS).1. Finite element analysis of the clamp-band unlocking support. Patran/Nastran softwares was used to develop three dimensional finite element model of the support, and the pretension loading progress and axial loading case are simulated. The results show that the bigger the friction coefficient, the faster the stress of band reduce along the circumference, and the bigger the uneven degree of the stress of band and contact force between band and support; At the same force of tension, the bigger the friction coefficient, the smaller the stress of the band, which shows bigger friction force can improve the bearing capacity of the unlocking support.2. Develop a analysis model for clamp-band unlocking support. The contact between convex block of band and groove of support is most worth concerning. The contact force, prestressing force, friction force of contact surfaces and the relationship among them are analyzed, the analysis results coincide with the results of finite element calculation. In order to realize the combination of finite element method and the analysis model, the analysis model is introduced into virtual work equation of system. The finite element formulation of analysis model is derived based on beam element, and further, the equivalent nodal force vectors are derived. This provide foundation for solving dynamics problem of this kind of clamp-band connection.3. Modal analysis and screw connection modeling. Support test piece was modal analyzed through the experiments and FEA to quantitatively study how the methods of screw modeling affect the results of FEA. The studies showed that the modeling method plays an important role in analytical error. The result of FEA with conjoint nodes at screws displays an error of less than5%to the result of experiment. The result of FEA with modeling screws displays an error of5%-10%, but this way significantly increased the calculation. Using Rbe2element to simulate screws connection only increase few nodes and elements for whole component, and it can keep the error within5%, which brings great convenience to finite element dynamic analysis.4. Research on shock environment of the supports when unlocking. In order to ensure the safety of the satellite and the camera equipment, shock environment of the support need to be studied. This chapter firstly take tests, analysis and improvement for the protection board, and then measured the shock that unlocking support imposed on the structure. The predicted analysis was taken through FEA software, and finally, the test and calculation results were SRS processed. The results show that the TC4can better meet the quality and deformation requirements, and proper reducing preload of clamp band can lower the structural shock response, and the vibration generated by the release of strain energy dominates in the unlocking shock; Unlock impact is mainly composed of release bearing strain energy release cause, modeling analysis its impact environment negligible explosion shock composition; and the finite element analysis can estimate the low frequency shock environment with sufficient accuracy. These conclusion provide reference for the design of this kind of device and the preanalysis of shock environment.