【作者】 李忆；

【导师】 邹青；

【作者基本信息】 吉林大学 ， 机械制造及自动化， 2007， 硕士

【摘要】 本论文题目来源于中国科学院空间科学与应用研究中心,该单位委托吉林大学研制圆锥扫描辐射计平台及天线展开机构。由于圆锥扫描辐射计平台及天线在上天的过程中会受到不同程度的动态冲击或载荷(主要是振动载荷),所以,针对振动载荷对其进行模态分析就成为了本文的主要内容。本文针对模态分析首先介绍了有限元法和有限元法典型分析步骤,并介绍了分析软件及其分析问题的基本方法和基本步骤,详细说明了模态分析的基本原理和基本方法。为了使分析过程顺利进行,在进行模态分析之前,本文还讨论并提出了模型的简化方案和利用分析软件分析时所需的材料类型。接着,本文又分别对天线展开机构和平台的主要零件进行了模态分析试算,验证了模型简化方案的可行性,总结出了影响基频的几种因素,并说明了其中的原因。最后,本文重点对天线展开机构和旋转平台机构中的几个主要零部件进行了模态分析的正式计算,并分别得到了这些零部件的固有频率和固有振型的分布情况。根据这些结果分析出了危险点的位置,并提出了一些降低危险的方案。本文所得到的分析结果都将会为以后的进一步优化设计提供良好的依据,进而为后续的正弦振动试验、随机振动试验、冲击试验提供了前提条件和准备。更多还原

【Abstract】 The title of this paper originates from The Space Science and Application Study Center of Chinese Academy of Sciences, this unit have entrusted Jilin University to develop“The Cone Scanning Radiation Platform and Unfold Mechanism of Antenna”. The Cone Scanning Radiation Platform and Unfold Mechanism of Antenna will suffer the dynamic impact or load (mainly is vibrating load) during it is being launched, so it is very important for it to be carry on dynamic analysis. I have joined the whole research process of the project, and there are few examples for antenna using modal analysis to carry on the vibration analysis, so the modal analysis is the main contents of this paper. What is described in this paper is one of the most important works in this project, so it is very realistic and applicable.There are a lot of harmful vibrating problem in mechanical industry and other industry section. Some large and high speed rotary machines have resulted in important and malignant accidents many times because of the dynamic losing steady at domestic and abroad. Sometimes, some large engineering structures have also resulted in some accidents because of vibration. In addition, the excessive vibration and the noise because of vibration also pollute environment, and also injure people’s health. These problems have been resulting in great lose or hiding terrible roots of trouble. Science technique having developed till today, the vibrating analysis and control is not superfluous for many engineering projects, but is a necessary measure deciding the destiny of a project. It is very important to study and solve these problems with the theory, technique and method of the vibrating engineer.There are a lot of vibrating forms for machines, buildings, aerial aircrafts, ships and automobile. The modal analysis has provided a validmethod for studying various actual structural vibration. In lots of aspects such as the vibrating character analysis, vibrating control, trouble test and forecast, and noise control of aviation, automobile, machines, electrical machine and bridge, there is a very extensive application for the technique of modal analysis. The modal analysis is a modern method studying the structural dynamic characteristic, and is an application of the system recognizing method in the field of engineering vibration. The technique of modal analysis is an old and developing subject, in the last few years, the technique of modal analysis has been from the traditional theory of linear displacement modal change to broad sense modal theory, and is leaded to the field of non-linear structural vibrating analysis. The modal analysis is mainly carry on vibrating analysis to the mechanical structure, and is a technique to confirming structural vibrating characteristic which include intrinsic frequency, vibrating form, and so on. The modal analysis is the most basic work in all of types of dynamic analysis.First, this paper introduces the Finite Element Method (FEM) and the process of the Finite Element Analysis (FEA) for the modal analysis. In the process of mechanical structural dynamic analysis, creating structural dynamic model is with the finite element method of flexible mechanics, and it could compute the structural modal parameter such as intrinsic frequency and vibrating form, and it could figure out the dynamic response (including displacement and strain of response). Second, this paper also introduces the software of ANSYS and its basic method and process of analyzing problem, and explains the basic principle and method of modal analysis.For making analytical process smoothly progress, this paper also discuss some methods of model simplify and the needed type of material before the modal analysis.This paper is also carry on the tentative calculating of the modalanalysis for the platform and unfolds mechanism of antenna, and verified the validity of finite element model, and confirmed the constraint method of model, and got the relation between the frequency and material (carbon fiber and titanium alloy) characteristic. This paper verified the possibility of the model simplify, and discussed some factors of influencing frequency.This paper is emphatically carry on the formal calculating of modal analysis for the unfold mechanism of antenna (including truss frame mechanism and crossing mechanism) and the main components of rotary platform (including fixed platform, supporting axis, rotary platform and rotary axis), and got the intrinsic frequency and vibrating form of them. Basic these result, this paper have analyzed the dangerous position, and put forward some method of decreasing dangerous.This paper verified the rationality of the unfold mechanism of antenna and rotary platform, and then it provides the prior condition and preparation of sinusoidal vibration test, random vibration test and impacting test.更多还原