Foaming Behavior of Polyurethane to be Applied to Inflatable Space Structures under Low Pressure Environment
Hatta Hiroshi; Udagawa Atsushi; Higuchi Ken; Yokota Rikio; Sugibayashi Toshio
Abstract:Inflatable space structures are expected to be a promising candidate for future large scaled space structures because of the compactness at the launch stage and the simple extension mechanism. In this paper, the feasibility of an inflatable structure was examined utilizing the expansion force of foam materials as the inflation thrust. As a trial inflatable space structure, an extensible mast, which was made of foam material covered with an aluminum sheet or a carbon fiber cloth was chosen. This paper describes foaming behavior of the material in space. As a first report of the study, intensive discussion was placed upon the effect of low pressure environment on the expansion behavior. The expansion behavior of foam material appeared to be controlled mainly by the pressure difference between the inside and outside of foams. It was found that the fracture of foams could be prevented and the density of the foam material could be controlled even in the low pressure environment by controlling the amount of blowing agent. The effect of tube geometry on the expansion behavior was also discussed. Key Words:inflatable structure, space structures, foam materials, low pressure, foaming agent, expansion pressure