Buckling of curved shells with free edges under multi-axis loading

Tape hinge technology is of interest to designers of elastically deployable structures. Tape hinges consist of any number of singly curved shells, or tape springs, aligned axially and symmetrically. A tape hinge can replace traditional hinges by allowing for folding at the middle of the hinge when the shells are flattened yet resisting beam-like loads when unfolded. Despite their use in many space applications, it remains difficult to predict the deployed strength performance of tape hinges without experimentation.; An analysis of tape springs is completed in this thesis using the Donnel-Mushtari-Vlasov shell theory for symmetric laminates in a non-dimensional finite difference method to determine a general understanding of the influence of shell geometry on deployed strength performance. Previous work in this area is extended to include the combined effects of axial, moment and transverse loads. This loading combination is of particular interest to tape hinges because of the loads they must withstand in a structure. The effect of transverse loading is added to the analysis by a linear variation in moment along the length of the tape spring analogous to the behavior of a beam.; A controlled displacement experimental apparatus is built to apply any desired planar translation and end rotation to a tape spring in order to mimic the motion a tape spring may undergo in a tape hinge. A total of sixty geometric and loading combinations are tested. Experimental results show that the effects of small transverse loads can have a significant effect on the deployed strength of a tape spring. This behavior is approximated in the new shell formulation and the limitations of this model are discussed.; Predictions from the theory are compared with experimental results and finite element predictions. In one case the theory predicts a critical axial load knockdown of 40% for a transverse to axial load ratio of 2%. The theoretical predictions over predict the buckling loads by 20 to 50% with the difference being significantly dependent on the buckle shape and shell aspect ratio. Reasons for this discrepancy are discussed.*; *This dissertation is a compound document (contains both a paper copy and a CD as part of the dissertation). The CD requires the following system requirements: Windows MediaPlayer or RealPlayer.