Analysis Of Similarity On Hoop-rib Deployable Antenna

With the increasing requirements of space application, the aperture of the space deployable antenna is demanded larger and larger. However, it is very difficult to carry out some experiments on the antenna because of the large aperture and the limitations of the ground environment, such as fields, expenditure and testing equipment. Once some wrong happens, it will make great of waste both on manpower and material resources. Because the scaled model has a small aperture and can be made and do experiments on easily. This paper use the small antenna which is similar to the large one to do the performances testing. In other words, we can dope out the performances of the large model by studying the performances of the small model. It is a feasible method.The research object of this paper is hoop-rib deployable antenna. Firstly, the development of the deployable antenna and the basic contents of the similarity theory are introduced. Secondly, the scaling laws on statics between the prototype and the scaled model are analyzed in the case of complete similar. The model's performances are forecasted respectively through mathematic expression which is infered by similarity theory and ANSYS computer simulation when the mass of the joints have some distortions. Two different methods get the same conclusions, so the rationality of prediction of the similarity theory is validated. Moreover, when the density of the bars and the size of the hoop-bars have some distortions, the prediction arithmetic expressions of the structure frequency and structure RMS are infered. Thirdly, using two different methods of the similarity theory which are the differential equations and the dimensional analysis method, work out the scaling laws on dynamics in the case of complete similar. When the area of bar's cross section has a distortion, the prediction expression of the time that the antenna to deploy is analyzed. Then, forecasting the time that the scaled model to deploy is worked out by ADAMS computer simulation. Two different research methods get the same results, so the mathematic expression infered by similarity theory is proved right and the method of forecasting by similarity theory is feasible.The results of similarity analysis and simulations of this paper show that we can use the scaled model instead of the large one to do the perfoemances tests so as to forecast the performances of the large one. The large one and the small one which are similar models have the similar features on statics, dynamics and so on. Though the model exists some distortions, we can modify the coefficient and continue to forecast the performances of the prototype. The meaning of this paper lies in that it can provide some referrences and design parameters for the antenna which has a large aperture. The method of similarity analysis can be also used in other space structure design and to forecast the performances.