Surface Analyses And Optimizations Of Inflatable Deployable Membrane Reflector Structures

With the development in the regions like national defense, aerospace and telecommunications, the requirement of inflatable-deployable membrane reflector antennas has been increasingly raised. The reflector surface accuracy in working state is an important indicator for the reflector antenna in the view of structure. It will reduce the antenna gain, lose the working efficiency and influence the electronic properties if the reflector surface accuracy cannot match up with expectant value. Therefore, it cannot be neglected for the study of reflector surface accuracy to inflatable-deployable membrane reflector antennas.The inflatable-deployable membrane reflector antenna is treated as the study object. Based on a bunch of references, the applications of inflatable-deployable membrane reflector structures have been introduced. The key technologies of inflatable-deployable membrane reflector have been stated. The previous research for inflatable-deployable membrane reflector has been reviewed. The significance for this research has been declared and the research major has been determined.Firstly with regard to the membrane reflector surface solution of initially non-stressed state, the analytical solution with concerning orthotropic membrane material has been derived. The effect of different boundary conditions on the undetermined constant has been studied. The discontinuous problem on the reflector center on rotation axis has been discussed and explains and measurements have been stated. On the basis of inverse iteration and weighted form finding method from numerical analysis, a kind of highly precise modified inverse iteration method has been proposed with concerning the nodal displacement deviations on the vertical axis projection plane during each nonlinear finite element analysis iteration step.Secondly with respect to the optimal analysis of membrane reflector surface accuracy, a kind of reflector thickness optimization method based on the structural topology optimization has been proposed. The reflector thickness optimal model has been set up and the derivative of objective function has been derived. The filter method has been employed to develop the thickness optimal result and to get the ideal minimum radius.Thirdly about membrane structure deploying process simulation, a kind of membrane element deformation presentation in local coordinate based on finite element method has been declared to apply in finite particle method. A kind of developed triangle membrane element constraint Jacobi matrix has been declared to apply in Moore-Penrose-inverse-matrix-based form analysis. The codes for these two methods have been made. The membrane reflector folding proposal in the form of tapered Miura pattern has been given.Then concerning a kind of 1800mm-aperture inflatable-deployable spherical antenna, the material tests have been carried out. The reflector tailor forms have been made and the cut-parts have been calculated. The process and procedure of this spherical antenna has been studied. The antenna properties have been carried out.Finally as to the parameters of this spherical antenna, the relative mechanical analyses have been conducted to assess the effects on the reflector surface accuracy, including the pressure in initial working state, rope arrangement with wind load in the static analysis, structurally natural frequency analysis and thermal analysis with unitary temperature transformation.With a series of theoretical derivations, codes and numerical examples, it is indicated that it is helpful to improve the surface accuracy by the reflector initial non-stressed state profile analysis. It also indicated that it can largely improve the surface accuracy by reflector thickness optimization method based on the structural topology optimization. The feasible reflector folding management can keep the deploying process orderly and stable. With a series of designs, analyses and tests, it is shown that this inflatable-deployable spherical antenna has good antenna properties and stable surface accuracy.