Designing Of Shaped-Antennas On Satellites And Designing And Analysis Of Cable-Membrane Structures

There are two parts in this dissertation.According to the topic supported by pre-research foundations in the tenth-five plan of the Chief Equipment Department we do the research work on shaped antennas. The form-finding of satellite-loading shaped antennas is actually a course of finding a optimal curved surface, whcih means the common and traditional surface would be adjusted so that the new surface could make the practical service area cover the expected service area to the most degree. The dissertation introduces several of the shape-finding ways and compares them, and then the strongpoints and flaws are present. Grid phase method, one of them is chosen to be combined with a traditional method, so that we get a new method of re-designing to find proper surface for a shaped antenna. This method is based on the previous way, adopting the new way, in which the two ways are connected tightly by "optimal wave-distance". At the same time a sample has proved the method feasible and it can be realized in the application.Cable-membrane structures have been more and more common in the recent years. They cost less construction time with beautiful apperance so that they are playing an important part especially in public buildings. The essence of the designing of membrane structures is also to find the optimal structure surface under the constrain conditions of boundaries. In the dissertation three main methods of form-finding are present: Finite Element Method(FEM), Dynamic Relaxation Method(DRM), Force Density Method(FDM). Based on the programme of Ansys, FEM has been illustrated from another point. In the course how to find the right surface and what problems will appear and and corresponding solving measures are discribed in detail. This dealing is convenient,whcih has proved practical by an example. In the meantime FDM has been worked on particularly. Some problems on dispersing membrane into dicrete nets in the previous papers are pointed out and settling steps are brought forward, so that the analysis course will accord with the facts better. In the end the How to analyze the load on cable-membrane structures is prsent. The analysis includes pre-stress loads, out-of-plane loads and wind loads analysis. For the out-of-plane loads analysis attached elements are used to make the computions converge more easily within the tolerance; for wind loads, examples prove the fluid-solid coupled analysis feasible and applicable. These work has provide some reference for the construction designing on how to make use of FEM.Designing and analysis of cable-membrane structure is a hot topic and there is much research work left to do.