Folding, Stowage and Deployment of Viscoelastic Tape Springs

This paper presents an experimental and numerical study of the folding, stowage, and deployment behavior of viscoelastic tape springs. Experiments show that during folding the relationship between load and displacement is nonlinear and varies with rate and temperature. In particular, the limit and propagation loads increase with the folding rate but decrease with temperature. During stowage, relaxation behavior leads to a reduction in internal forces that signi cantly impacts the subsequent deployment dynamics. The deployment behavior starts with a short, dynamic transient that is followed by a steady deployment and ends with a slow creep recovery. Unlike elastic tape springs, localized folds in viscoelastic tape springs do not move during deployment. Finite element simulations based on a linear viscoelastic constitutive model with an experimentally determined relaxation modulus are shown to accurately reproduce the experimentally observed behavior, and to capture the e ects of geometric nonlinearity, time and temperature dependence.