A tape spring is a thin-walled, straight strip of material with curved cross-section. Metallic tape springs have been used for many years, but the current trend is towards tape springs made of carbon fibre reinforced plastic (CFRP), for their tailorable properties, low mass and low coefficient of thermal expansion. The moment-rotation behaviour of a tape spring can be described as linear-elastic for small rotations and constant-moment for large rotations. Simple analytical expressions for fully characterizing this response, for a general tape spring made of CFRP, are presented in the paper and the accuracy of these expressions is assessed by means of detailed, non-linear finite-element analysis.

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This paper is concerned with self-powered, self-latching tube hinges, made by cutting three parallel slots in a thin-walled carbon fiber reinforced plastic tube with a circular cross section. Thus, a hinge consists of two short tubes connected by three transversally curved strips of material ͑known as tape springs͒. A particular tube hinge design is considered, with a diameter of about one-third that of the hinges used previously; this requires the tape springs to reach strains close to failure when the hinge is folded. Three analyses of the peak strains in a tube hinge are presented. The first analysis obtains general analytical expressions for the longitudinal fold radius of a tape spring and the associated peak fiber strains. The second analysis is a finite-element simulation of the folding of a single tape spring and the third analysis is a simulation of a complete tube hinge. It is found that the largest fiber strains in one-and two-ply hinges can be predicted analytically with very good accuracy. It is also found that the contact and interaction between the three tape springs that form a tube hinge, modeled in the third analysis, do not affect the peak strains significantly.

This paper investigates one-ply and two-ply laminates made from woven T300 carbon fibre and Hexcel 913 and 914 epoxy resins. These laminates are of interest for deployable structure applications. The maximum surface bending strain, measured by means of a large-displacement buckling test, is found to be 2.8% for one-ply and 1.9% to 2.2% for two-ply specimens in the direction of the fibres. In tension the maximum strains in the fibre direction are 0.9% to 1.0% and in compression 0.4% to 1.0%.