Corner Wrinkling of a Square Membrane Due to Symmetric Mechanical Loads

Thin-film membrane structures are under consideration for use in many future gossamer spacecraft systems. Examples include sunshields for large-aperture telescopes, solar sails, and membrane optics. The development of capabilities for testing and analyzing pretensioned, thin-film membrane structures is an important and challenging aspect of gossamer spacecraft technology development. Results are presented from experimental and computational studies performed to characterize the wrinkling behavior of thin-film membranes under mechanical loading. The test article is a 500-mm-square Kapton membrane subjected to symmetric corner loads. Data are presented for loads ranging from 0.49 to 4.91 N. The experimental results show that as the load increases the number of wrinkles increases, while the wrinkle amplitude decreases. The computational model uses a finite element implementation of Stein-Hedgepeth membrane wrinkling theory to predict the behavior of the membrane. Comparisons were made with experimental results for the wrinkle angle and wrinkled region. There was reasonably good agreement between the measured wrinkle angle and the predicted directions of the major principle stresses. The shape of the wrinkled region predicted by the finite element model matches that observed in the experiments; however, the size of the predicted region is smaller that that determined in the experiments. (Author)