Satellite Antenna Structure Co-vibration Response Analysis

Paper number

IAC-07-C2.3.06

Author

Prof. Juanfang Wei, China Academy of Space Technology (CAST), China

Coauthor

Dr. XiaoFei Ma, China Academy of Space Technology (CAST), China

Coauthor

Mr. Bo Gao, China

Coauthor

Mr. yonggang fang, China Academy of Space Technology (CAST), China

Year

2007

Abstract

During the satellite antenna vibration test, the co-vibration happens when different components have the same Eigen-value or the first Eigen-value mode is the elastic mode of base supporting components or middle main structure. In the case of co-vibration, measuring curves show the scale of antenna acceleration response verse input acceleration level are much bigger than the normal scale which is usually defined by the damping of material and structure. The scale also increase sharply as the input level increase and this is a common reason that causes the structure damage. Linear FEA model usually can not predicts this non-linear vibration response, as the connector screws usually are modeled into a beam or a rigid bar. This kind of modeling method cannot exactly represent the real connecting status as the two connected interfaces also knocking each other during vibration. Another reason for analysis error is the sine or random response analyzing is treated as exactly along the X,Y or Z direction, but the real vibration shaker also have rotating movement in some extent as the mass center of antenna usually has some offset distance to the center moving line of shaker. This mini rotating movement also inspires some of rotating modes. This paper improve the FEM model in three aspects:meshing the connectors and the area around into three dimensions solid elements, treating the connector interfaces as contacting relationship, adding some rotating acceleration input to shaker’s moving acceleration input. Analysis results fit the test response curves well. To lowest the maximum acceleration response of antenna during launching, the best stiffness design principle for satellite antenna is just like a structure of tree. Eigen-value of each component should be, from low to high, first leaves (such as reflector or feed), then twigs or branches (such as main supporting structure or bracket), last root (such as mounting plate or fixing connectors between antenna and satellite) . 
 
Announcement by Authors
The material used in this paper is new and original. The paper was not presented at a previous meeting. The financing and attendance of an author at the respective 58th IAC to present the paper is assured. 

Abstract document

IAC-07-C2.3.06.pdf

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