Stability Analysis of Coiled Tape Springs

Abstract

Tape springs have been used for many years in deployable booms and space mechanisms and currently are bing considered as components for more advanced deployable structures. Tape springs can be elastically coiled and will self-deploy when released. Their stability in the packaged configuration is critical for these applications. We propose a numerical and analytical framework to investigate the stability of coiled isotropic tape springs, where neither tension nor radial pressure are applied. Torsional and bending instabilities were observed when the ration between the coiled radius and the radius of the cross-section exceeded a critical value. A stability boundary is derived for different geometries and material properties. The effects of varying the number of coils and the self-contact conditions between adjacent loops of a tape spring are also studied, and the existence of out-of-plane instability modes is discussed.