Deployable Trusses Based on Large Rotation Flexure Hinges

Abstract

Formulations for the strength, stiffness, mass efficiency, and packaging of deployable trusses using flexure hinges are developed and comparedwith the experimentwithin. The equations are based on classical buckling theory, Euler buckling with engineering approximations, and finite element-based models to predict the column and bending strengths of solid rod and tubular trusses with slender flexure hinges. Flexure hinge material performance metrics are derived and used to show that, while bothmass efficient trusses of solid rods and trusses of tubes are feasible with existing materials, trusses of solid rods are significantly more strain limited. A representative high compaction ratio deployable truss with pultruded carbon fiber reinforced plastic rods and super elastic nickel-titanium alloy flexure hinges was fabricated and tested. The compressive strength of the truss was 48% less than predicted and the compressive stiffness of the truss was 12% less than predicted.