Nonlinear finite element model for the analysis of axisymmetric inflatable beams

• A nonlinear finite element model for axisymmetric inflatable beams is developed.
• The model simulates the performance of inflatable beams with numerical examples.
• The wrinkling phenomena is studied with the proposed model.
• Results show that wrinkling load is proportional to the square root of inflation pressure.
• The relation between wrinkling load and radius of the cone varies from cubic to linear.

Inflatable structures are already being used for decades now especially in aerospace applications. The Inflatoplane and inflatable space habitats are just examples. On the other hand, the modeling and simulation techniques of inflatable structures are lacking far behind. Most of the available models are concerned with cylindrical beams. In this paper, a nonlinear Finite Element model for axisymmetric inflatable structures is developed using beam elements. The model is validated by comparing its predictions to two cases of cylindrical beams in the literature. The model is then utilized to predict the effect of two parameters on the wrinkling load of the beam. Results show that the wrinkling load is proportional to the square root of the inflation pressure. For the beam radius, it is proportional to the cube of the radius at small radii but then the relation is linear afterwards. The model is also used to predict the performance of an inflated truncated cone as a function of the inflation pressure and the root radius. The proposed nonlinear Finite Element model is a step towards analyzing real-life inflatable structures.