Research On Key Technical Issues Of Spaceborne Deployable Structures

The deployable structure installed in the satellite, namely Spaceborne Deployable Structure, is an important part of the satellite structure. It is also an important platform to directly implement functions of the satellite. Therefore, its implementation technology directly affects the satellite technology. Based on deployable structure of Zhejiang University micro-satellites II, several of its key technical issues problems were studied.Firstly, on the basis of referring lots of pertinent literatures world-widely, It was introduced the research status of deployable structures and the latest progress of small satellite technology. Then it was focused on the development process of the Zhejiang University micro-satellites II deployable structure and the significance of the project results.In order to guarantee the reliability of the locking and unlocking for the prestressed deployable structure on the micro satellite, a new type of the thermal knife restraint and release system was developed. The theory and composition of this device were introduced and the electronic thermal element was improved. Thermal simulation analyses and electric performance tests of this device were carried out. On the basis of the parameter compares and tests for the cord, a kind of Dyneema cord was selected and its creep control was stated. The tests were conducted to study the relationship between cord pretension, average unlocking operation time and structurally natural frequency in folded locking state. Then the exact value of this pretension was determined. A standardization device and proceeding program were developed to process the pretension for the cord. Finally, the unlocking function test was employed to verify the feasibility of this device.Due to the lack of specific criteria for the spaceborne deployable structure in prestressed folded state and the difficulty for matching with mechanically environmental requirements in rocket active flight state, a kind of criteria was put forward to determine the entire star "stable" folded state. The finite element analyses and related experiments were carried out for structural strength and stiffness of this "stable" folded state as a kind of reference for the following study. Based on this spaceborne prestressed developable structure, the tests were conducted to study the relationship between cord pretension and structural natural frequency in folded locking state and the average locking operation time. Then the value of this pretension was determined. The intensity and modals of the entire structure in "stable" state were computed by ANSYS software. The rationality of the finite element analysis results was verified by comparing the shaking-table test with hammering method for fundamental frequency measurement.Depend on the system level, the classical theory of fault tree analysis and ADAMS software simulation,the reliability prediction and analyses were carried out. The results showed that the design of deployable structure is reasonableand it has high reliability and meets the demands of spaceflight.Finally, it was provided the entire structure assembly process in order to provide installation instructions for the staff and the installation coordination.