Deformation Research Of Inflatable Envelope Of Airship

Analysis of global and local deformation plays an important role in the analysis of stratosphere airship structure, which is a kind of pneumatic membrane structure with the characteristics of large curvature and large volume, besides its flexible characteristic. Analyzing global and local deformation of the inflatable envelope can be helpful in structure manufacturing and in equipment installation, such as energy system, propulsion system and other external carrying system. Meanwhile, service life of stratosphere airship can be predicted by deformation in certain external environment. Therefore, research in deformation of airship envelope do practical significance in manufacturing stratosphere airship.A typical kind of trilobites rose line was selected as the shape of airship envelope, classical theories of mechanics and commercial finite element software were the two tools used in analysis. The control variable method was adopted in research of the deformation, which is mainly influenced by four resistance indexes and three load indexes.Firstly, classical theories of mechanics were used in statics analysis of airship, and range of pressure was determined, stress and strain of airship were deduced. At the same time, application of Timoshenko beam theory was verified to be accurate when analysing pneumatic membrane structure.Secondly, to deal with the characteristics of large curvature and large volume flexible of the airship, a general method has been proposed based on finite element method. Mesh is a difficult work since the large curvature in head and tail of the airship, and even if meshed and modeled perfectly, it is still possible that calculation is not convergent. Aimed at this situation, this article put forward a practicable solution. What’s more, how to determine the boundary conditions of the airship is one of the key issues in the static calculation of airship, since airship is suspended in the air. There are two kinds of solutions for the problem at present. One is inertial releasing technology, the other is restrictions in some appropriate points. Two kinds of methods were compared explicitly in this paper, and their application fields were pointed out.Finally, using the above finite element method, the influence of four resistance indexes, namely, elastic modulus of materials, poisson ratio,length of airship envelope, slenderness ratio, on deformation were calculated, and laws were obtained through analyzing. The influence of three load indexes, namely, pressure, gravity load, hanging load, on deformation were calculated, and laws were obtained through analyzing.