Structure Design, Analysis And Test Study For Deployable Truss Structure

Following the development of the aeronautical technology, higher request was brought forward to deployable antenna on satellites from every relative field. A lot of structural concept for deployable antenna was given out by aeronautic scholar. As a new kind of structure, the deployable structures are more and more widely used in the fields of astronautics, building structure and military engineering, etc. They can be divided into space deployable structures and ground deployable structures. In space deployable structures, tetrahedron deployable truss structure is a promising kind, which has most potential for space application. So it is an important content of this paper. This dissertation presents a program that used to design a tetrahedron deployable truss antenna, then analyzes and test for this kind of antenna.Firstly, after referring a lot of pertinent literature world widely, the application of deployable space structure and the research actuality of its deployment process were summarized, the research significance is presented.Afterward, based on the antenna design theory, this dissertation describes a wayto develop a program for designing tetrahedron deployable truss antenna. It uses the lisp which is the secondary development tool of AutoCAD to visualize the solid model of antenna. With this program, one can easily build a solid model in any dimension. Then we design and fabricate a 2m*2m antenna to test the program. The result seems quite well.After built an antenna, besides its deployability, the designer usually cares much about its surface error. So a non-contact Photogrammetric measure system was built on the base of PhotoModeler software packages to measure the surface error of an antenna model with 2 m caliber and 6m*2.8m caliber, and get their node coordinates. Then uses three methods to fit paraboloid and program it. Also this paper uses Mathematica to fit paraboloid. Finally the best fit paraboloid and least RMS are obtained.According to the structure design theory, all of the nodes in tetrahedron deployable truss antenna are not well proportioned; their angle is not 60°but close to this angle. This dissertation wants to make the nodes to be identically in 60°, thus there is internal force in antenna. So it is necessary to analyze the internal force. Suppose the internal force is constantly in deploying process, and then it can be added in the Deployment Dynamic Analysis Program and study its impact to deploying process.Spaceflight launch is an expensive project, once failed, the cost is huge. So it is necessary to take reliability study. This paper breaks up the antenna joint function and find its movement reliability has two parallel performance functions: the performance function according to deploying work and that according to deploying moment; Corresponding to the decomposed phase in deploying process, the expressions of two performance functions were established. Then two-kind reliabilities can be calculated from the two performance functions by means of the random functional moment method and the second moment method for reliability analysis. The movement reliability of one deployable joint can be got from two parallel reliability models. Then establishes the failure function and analyzes the relations of deploying times and reliability. Also the dissertation uses Faulty Tree Analysis Method and Fuzzy Probability Method to analyze the reliability.After theory analyze, the mode test is taken on tetrahedron deployable truss antenna. Compare the test result and theoretical result to verify the finite model and confirm the test data.Use the deploying process simulation software for circular truss antenna to analyze a 30m antenna with tested cable force. Design two methods to hang the antenna and analyze the effect of gravity to deploying process. Consider the effect of mesh. There are rotational springs in nodes; the program also counts in its function. Finally the stiffness is analyzed during the deploying process of circular deployable truss antenna.