Carbon Fibre Reinforced Plastic Tape Springs

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.