Geometric scaling properties of inflatable structures for use in space solar power generation

Investigation of the geometric scaling properties of polyimide film inflatable booms is described. These structures have considerable potential for use in space with solar concentrators, solar sails, and space solar power systems including solar arrays. Multiple cylindrical test articles were fabricated, utilizing two different thicknesses of Kapton polyimide film and seven aspect (slenderness) ratios. Numerous static bending and axial buckling experiments were conducted and compared to computer simulations using the MSC/NASTRAN program. Both beam element models and shell element models were developed for several inflatable struts and compared to experimental test results. Several problems encountered during the construction, experimentation, and finite element analyses are described. These included creating the proper experimental setup for static testing and establishing the optimum finite element analysis process for the analytical models. Many of these problems were overcome in the course of the research. Using the results from both experimental and analytical aspects of the research effort, guidelines for appropriate analysis techniques and experimental test article design were determined. These can be used to approximately determine properties of large-scale structures, which can not be tested in laboratory experiments.