【作者】 侯国勇；

【导师】 关富玲；

【作者基本信息】 浙江大学 ， 结构工程， 2008， 博士

【摘要】 随着空间科技的发展,各相关学科对空间可展结构提出了更高的要求,主要体现在大口径、高精度两方面,为此各国学者提出了形式众多的空间可展结构概念。可展结构作为一种新型结构形式,近些年来得到了广泛的应用,根据其用途不同可分为空间可展结构和地面可展结构。在空间可展结构当中,四面体桁架式可展天线是其中最具潜力的结构形式之一,是本文研究的重点。本文对四面体桁架式可展天线的结构设计、分析及试验进行了深入系统的研究。论文首先在大量查阅国内外文献的基础上,总结了国内外空间可展结构的应用情况及研究现状,阐述了课题的研究意义。接着在四面体桁架式可展天线结构设计理论的基础上,开发了参数化仿真建模程序,使用AutoCAD的二次开发工具,通过lisp语言在AutoCAD中显示整个天线的实体模型;更改输入参数,可建立任何尺寸天线的实体模型,然后运用该设计程序设计并句口工了一个2m×2m的天线模型,验证结构设计程序的可靠。天线设计完成后,除了要能顺利展开之外,展开后能达到的精度也是设计者十分关心的指标,因此本文使用基于PhotoModeler软件建立摄像测量系统,对一个2m×2m的天线模型和6m×2.8m天线进行精度测量,得到天线的空间节点位置;然后采用的三种不同的方法拟合抛物面,并编程序计算;同时也采用Mathematica软件拟合抛物面;最后比较各种不同的方法,找到一个最佳吻合抛物面并得到最小均方根误差。根据结构设计可知,四面体桁架式可展天线的花盘节点不是均匀的60°,这给制造带来了很大的不便。本文研究了将天线花盘节点加工成均匀的60°时的装配内力,并编程序方便的计算这些装配内力。假设在收拢状态下,天线也有装配内力,且与展开状态下的内力相同,同时假设这些装配内力在展开过程中保持不变,然后修改基于广义逆理论编制的四面体桁架式天线展开分析程序,将装配内力引入程序中,分析其对天线展开过程的影响。航天发射是一个昂贵的项目,一旦失败,损失是巨大的,因此对空间展开结构的可靠性研究是非常必要的。论文从研究单个关节的可靠度出发,分析指出了其运动功能可靠性中包含了矩的功能函数和功的功能函数这两个并联的功能函数;利用随机函数的矩法和可靠性分析中的一次二阶矩法,为天线的展开过程中的各个分解步骤构建了按矩的功能函数和按功的功能函数对应的可靠度计算表达式;然后构建关节的失效概率函数,进一步分析其展开次数与可靠度的关系;接着使用故障树的分析方法和模糊可靠性分析法来分析整体天线的可靠度。在进行了理论分析和仿真软件的研究之后,通过垂击法对四面体桁架式可展天线进行模态测试,然后将测试结果和有限元分析结果进行对比,验证天线的有限元模型,得到天线的模态数据。用基于广义逆理论编制的环形桁架天线展开过程分析程序进行计算,分析了展开过程中驱动力的变化规律及引入运动方程的方法;选择地面零重力模拟时的两种悬吊方式,分析不同悬吊方式对展开过程的影响;考虑了网面对展开过程的影响;为了使结构在初始展开阶段易于展开,在节点上安装了扭簧,论文分析了扭簧对展开过程的影响;最后对环形桁架天线在展开过程中的刚度进行了分析。更多还原

【Abstract】 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.更多还原