Experiment Research On Deformation Behaviour Of Inflated Membrane Structure Under Suspending Loading

Membrane material is used in many actual engineerings with assorted structure forms, which well expressed many merits of membrane structure. But in navigation aerospace field, especially in the high altitude stratosphere, the research on structure force and deformation of flexible airship is still not mature.In this paper, experiment method and process of uniaxial and biaxial tension of membrane material are introduced. The uniaxial tension stress-strain curves show that the membrane material is linear ultimately, within the range of 15% ultimate strengths. Occording to domestic and international tension experiment regulations as reference papers, 4 constants on mechanics performance of perfect orthotropic membrane material which is applied for inflated membrane structure are calculated. The biaxial tension experiment data is handled and analyzed by Least Square method, and the elastic modulus and Poisson ratio of this membrane material are made sure.The experiments about inflated membrane structure are carried out under the different suspending modes and differential pressures, and the general laws on deformation of inflated membrane structure are analyzed under the suspending loading, also its deformation behaviour is discussed. The deformations about the length and diameters along the horizontal and vertical direction, also suspending points of hull are described in detail under different suspending modes. Under the different differential pressure, the effect to the horizontal diameter change is not heavy under different suspending modes. With the dorsum suspending, a local hollow evidently is occured at the dorsum side of the hull. At the two side suspending mode with thin beam, the local deformation of suspending points at the beam is not obviously, and the amount of the deformation is generally the same as that of diameter, thus this suspending mode could be applied in large inflated membrane structure.The stress and deformation of inflated membrane hull are analyzed by the nonlinear FEM, and numerical simulation analysis of the inflated membrane hull is carried on by ANSYS, and the simulation results are contrasted to experiment results and theory calculated results, their varying trends of hull deformation are same. The difference between simulation and theory calculation of the surface stress of the hull are small, and the average difference between radial stress and ring stress is 7% and 2% respectively. The ratio of their ring stresses to radial stresses equals nearly to 2:1.