Precision And Deployment Analysis Researches For Membrane Inflatable Antenna

To realize large caliber, low-power, light weight, limit volume of the satellite antenna, compare to mechinics deployment antenna, the inflatable antenna structure technology have many advantages and is one of the best choice for large antenna. The shape precision of reflector on orbit is the most important target of the antenna, which affect the electric and work performance of the antenna directly. Whether the inflatable antenna can deploy to final configuration reliably is the key point that spaceflight mission can be successful. The theories to obtain high precision of inflatable reflector, wrinkle analysis technology and the deploy dynamics simulation of inflatable antenna are investigated in this thesis.Firstly, after referring a lot of pertinent literature world widely, the application of inflatable antenna structure and the research actuality of its key technology were summarized. Also the research significance is presented.Geometry nonlinear FEM of membrane was described by tensor form 9 node Lagrangian element and 3 node element was selected for membrane and 2 node linear element was selected for cable. Hypothesis damp term method was advanced to analyze non-prestress membrane structure. This method solved the problem from the singularity of stiffness matrix. The nonlinear FEA program for inflatable structure was compiled by FORTRAN and MATLAB.To obtain high precision of inflatable reflector, two kinds of figuration theories were investigated and compared. The first one is titled as plan- parabolic reflector. The elastic theory analysis was finished. Based on these works, the influence that temperature variety affects on the reflector precision on orbit was researched and the result was validated by FORTRAN program. The second one is titled as seaming parabolic reflector. For the deformed surface is required to be paraboloid, the theoretical studies, conformal analysis, cutting-pattern, membrane film seaming and then inflatable were described. The seaming parabolic reflector was chose in the following research.Precision analyses of inflatable reflector by nonlinear FEA program were conducted, and all important design parameters such as inflation pressure, membrane thickness, material characteristics and pre-tension stress of cable were investigated. The gravity influence in the reflector was compared under three postures and chooses one of them as final experiment posture. Analysis model of 2m antenna in ABAQUS was built to analyze natural frequencies and corresponding modes of the inflatable reflector structure. The analyses work has considered fluid-structure interaction between inflatable gas and the membrane material in reflector structure. This dissertation employed the 3D solid acoustic elements of standard FE software to simulate the inflation gas influence. The effects of all important design parameters on the modes were investigated.Wrinkling phenomenon exists broadly and affects the performances of the antenna structure. The distortion stress and strain of the structure were analyzed based on the source code written in MATLAB. Mixed criterion was used to evaluate the three states of membrane material: taut,wrinkled and slack. The TF method was used to forecast the direction and region of membrane wrinkle expediently. Then the wrinkle phenomenon appeared in inflatable reflector was investigated. A new method based on spring-mass system is advanced. This method can forecast not only the direction and region of wrinkle but also the shape and size of wrinkle.Some new fold patterns were developed for membrane structures from genuinely biomimetic. The spring-mass system is used to describe structural behavior of membrane material during deployment process. During development, self-contact or collision of the membrane occurs. The rule used to identify the self-contact elements is advanced and a penalty function method is developed to treat this difficult problem. The deployment processes of a two-dimensional membrane folded by three fold patterns were analyzed. The simulation code for inflatable membrane structure was described and the function of each part of module was introduced. The fold configuration and non-stress of tube, torus and parabolic reflector were built. The deployable mechanism and analytic model were researched to obtain deployable force and moment. The liquid theory was used to analyze the inflatable pressure in the ballonet. The deployment process was simulated by the code. Each state during deploy process and the velocity of each node were obtain. The simulation result validates the feasibility of fold method.A 2-meter ground demonstration space antenna reflector was design and manufactured. Non-contact Photogrammetric measure system was built on the base of PhotoModeler software packages. The steps of reflector precision measure of ultra-lightweight space structures were introduced on three experiment postures. High precision inflatable reflector was achieved after repeat precision measure and shape adjust. The error source of reflector was analyzed and shape adjust methods were introduced.