【作者】 张伟才；

【导师】 关富玲；

【作者基本信息】 浙江大学 ， 结构工程， 2004， 硕士

【摘要】 本论文共有两个部分。 根据总装预研基金“十五”课题，我们开展了星载赋形天线的研究。其形面设计是一个曲面寻优的过程，即要求反射面的服务区域和期望的服务区域能最大可能的重合，在这个约束条件下对原来的曲面进行调整。本文在比较清楚的介绍了赋形天线技术及其优点以及不同的找形方法后，对这些方法做出比较，然后选择了较方便的一种方法，即栅格相位法，和传统的天线赋形方法结合，进行二次设计，给出一种改进的设计方法。本方法利用传统的赋形方法为相位优化提供更简单的方式，提出利用“最优波程”来实现，这使得两种方法结合更加严密，形成一个整体。本文还通过算例验证这个方法的可行性，证明利用此方法是可以得到期望的赋形波束，实际中是可行的。 索膜结构的近年来应用比较广泛的一种结构，其施工快、造型美，在公共建筑中发挥了重要的作用。其本身也是在寻找最优曲面，其约束条件是边界。本文对索膜结构的主要三种数字分析方法有限元法、动力松弛法以及力密度法都有所论述。但主要是对有限元法和力密度法做了比较详细的工作。对有限元法，本文通过已有的程序Ansys作为平台，进行前处理，对索膜结构找形分析的有限元法从另一个角度做出解释，利用现有的单元来实现找形过程，这个过程中可能出现的问题以及采取相应措施尽可能的减小误差，这种方法方便、快捷，通过实际工程的证明是可行的。对力密度法，本文做了更详细的论述，指出了在以往的分析方法中离散膜片时出现的问题，并提供了解决方法来解决网格钝化问题，使得其分析过程和实际受力情况更为相符。最后本文详细的介绍了索膜结构的荷载分析过程，包括自应力荷载、平面外活荷载以及风荷载。对于平面外荷载，本文提出利用附着单元的方法使得计算在误差范围之内更加容易收敛；对于风荷载，利用实际例子来说明流固耦合分析的可行性与必要性。这些利用有限元进行各项数值分析的工作，为以后的设计提供了参考。 索膜结构的设计和分析是一个正在兴起的热点问题，还有很多工作需要进一步的深入研究。更多还原

【Abstract】 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.更多还原