Modal Analysis Of Cone Scanning Radiation Antenna

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.