Effect of boundary conditions on geometric control for an inflatable pathfinder system

The incorporation of inflatable structures into aerospace systems can produce significant advantages in stowed volume to mechanical effectiveness and overall weight. Many applications of these ultra-lightweight systems are designed to precisely control internal or external surfaces, or both, to achieve desired performance. The modeling of these structures becomes complex due to the material nonlinearities inherent to the majority of construction materials used in inflatable structures. Furthermore, accurately modeling the response and behavior of the interfacing boundaries that are common to many inflatable systems will lead to better understanding of the entire class of structures. This paper presents nonlinear finite element (FE) simulations performed to evaluate the effect of various boundary conditions on the geometric precision of a coated woven fabric panel representing typical internal/external surfaces commonly incorporated into inflatable structures. Altering geometry, loading level, and material direction of the fabric panel resulted in increased geometric control. The work presented in this paper is part of the development of an inflatable phased pathfinder system to improve efficiency of design and analysis techniques of future inflatable structures.