Numerical Analysis of a Tape Spring Hinge Folded about Two Axes

The ability to fold and unfold large sensor structures in space using hinges is important for space-based sensor technology. Tape spring hinges have become common in deployable space structures due to their simplicity, repeatability and unique folding properties. The mechanical response of these hinges (i.e., momen-tcurvature, energy stored) is important for deployment accuracy, safety and low cost of the structure. Finite element software, Abaqus_TM, was employed to analyze the folding and unfolding properties of a hinge using multidirectional bending. Uniform tape springs require a higher moment to overcome the curvature of the cross section when they are folded. In order to flatten the moment-curvature response of tape springs, a length of the middle segment of the hinge was first flattened, thereby removing the initial curvature about the long axis of the hinge. With the middle segment flattened, the hinge was subjected to opposite-sense bending about the hinge's short axis (axis perpendicular to the length of the tape spring). In addition to providing the means to determine stress (and potential damage) during folding and unfolding, the study determined the optimum method of hinge folding.