Research Of Mechanical Properties Of Inflatable Self-supporting Structure

With the development of lightweight and large-size deployment structure, the study of folding-unfolding of inflatable deployment self-supporting structure has become much more important. The thesis found the changing rule of mechanical parameters such as strain, unfolding moment and energy of the structure in the process of folding and unfolding through the study of a solar sail bracket with circular section and covered with self-supporting shell. The achievement can offer the study and design of space inflatable structure technical support.First, the thesis analyzed the folding and unfolding process of the thin shell which has curvature in the deployment mast and used finite element numerical simulation to simulate the process of folding and unfolding to achieve the variation conditions of strain and shape. According to the theory of thin shells, the thesis deduced numerical solution of stable bending moment of the shell in the process of folding and compared it with numerical simulation. The result of the latter one is coincided with the former one which means the method is feasible.Then the thesis analyzed the stiffness of the whole self-supporting deployment mast and carried out a series of experiences to test its compression stiffness, torsional rigidity and bending rigidity through electronic universal material testing machine. Meanwhile, the thesis simulated the stiffness of the structure through numerical simulation and analyzed the variation of its stiffness when it’s inflated with different inflation pressure to get its stiffness condition.Last, the thesis carried out dynamic characteristics analysis of the self-supporting deployment mast. The thesis analyzed the whole structure of the deployment mast through infinite element numerical simulation and dynamic characteristics method and achieved the primary four natural frequencies. The result of the two methods matched well. After that, the thesis carried out natural frequency test of the deployment mast under compression test and showed that deployment mast has perfect mechanical stability. The thesis also analyzed the structure’s dynamic characteristics under different inflation pressure and verified it with VIC-3D strain measurement system. The analysis indicated that inflation pressure had a large influence on the outer wall but little on the inner enhanced bar which can further verify that the natural frequency of the deployment mast is influenced most by the inner enhanced bar.