Continuous Multihinged Composite for Exoskeletal Applications
[Technical Report, Technical Report]
US Army Combat Capabilities Development Command, Army Research Laboratory
Pagination or Media Count:
This report investigates a lightweight, continuous-fiber composite multihinged structure employing dual-matrix materials for tailorable torsional stiffness behavior with intended application for exoskeletons. Interfacing such a composite into exoskeletons requires a balance between optimizing torsional stiffness while allowing for localized out-of-plane bending, mimicking the flexibility and load-transfer capabilities of a human joint. Directional stiffnesses are optimized through the design analysis via Classical Laminate Theory. The composite-hinge layup consists of layers of continuous woven Kevlar fabric with alternating regions of epoxy and flexible polyurethane film and additional layers of woven carbon fabric in the epoxy sections to increase stiffness. This reports breaks up the design, fabrication, and testing of the composite-hinged samples into two sections. The first section investigates the effect that changes in hinge properties have on torsional stiffness for single-hinge composites. Low-cycle testing is used to evaluate the torsional stiffness of each design through a novel offset bend test in a load frame. The second section uses the single-hinge findings for design of multihinged composites for integration into an exoskeleton prototype. A comparison is made with an existing exoskeleton prototype comprising 2-D woven-carbon laminate plates connected to 1 degree-of-freedom aluminum hinges and steel hardware.
- Anatomy and Physiology
- Laminates and Composite Materials