Center for Composite Materials - University of Delaware

Research Summary

Design and Manufacturing of Advanced Passive Dynamic Ankle-Foot Orthoses (PD-AFO) for Wounded Warriors – Open Manufacturing

Authors: S. Sharma, N. Khattra, S. Yarlagadda, Dr. Gillespie

Program Objective

Develop integrated design and manufacturing toolchain to enable rapid prototyping of composite Passive Dynamic – Ankle Foot Orthosis (PD-AFO)
• Rapid turnaround – 24 hrs is Objective
Majority of combat wounds are extremity injuries
• 26% are fractures, evenly divided between upper and lower extremities
• Surgical advancements leading to limb salvage and rehab
• PD-AFOs – rehab and enable soldier return to duty
Unique aspects of PD-AFOs
• Every one is different (individual customization)
• PD-AFO requirements change over time for same individual during rehab (tunable properties)
• Ideally needs very low profile (shoe wearable around it)
• Soldier loads high (high performance demands)
• Extreme durability (soldiers break anything…)
• Rapid turn around (can’t wait weeks to begin rehab)

Generalized Framework for Rapid Manufacturing of One

Implementation for AFO Rapid Manufacturing - Design Tables

Materials Database

Material selection
• <250 F cure
• Vacuum processing only
• Carbon fiber thermoset prepreg
Material qualification process
• Coupon testing
• L-bracket fatigue qualification to 3 M cycles

AFO Fatigue

Carbon Fiber AFO
• 3 Million cycle fatigue qualification
• Coupon S-N to derive fatigue criteria
• AFO qualified for 3M cycles, 1.45 safety factor post-fatigue

AFO Prescription and Manufacturing Workcell

AFO Workcell
• Modular workcell implemented at CCM
• Scalable to commercial AFO prescription

Technology Transition

Partner: Center for Intrepid, Brooke Army Medical Center
• Primary rehabilitation facility for OIF/OEF casualties who have sustained amputation, burns, or functional limb loss
• ~140 patients per month
• Ranges from limb salvage to full amputations Orthotist uses design tool and casts foot for tool

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