The design of a compliant shape-preserving ring

Compliant shape-preserving mechanisms fill a small niche within the established research field of compliant mechanisms. To date no report exists on a compliant shape-preserving ring, even though these mechanisms can give rise to a multitude of practical applications. They can essentially act as novel sealing mechanisms, compliant grippers or find use in medical applications. This paper presents three compliant shape-preserving rings that maintain their circular shape up to 99% for their full range-of-motion. The best design can expand in diameter by ≈ 45%. A prototype of a compliant shape-preserving ring was constructed from PETG (Polyethylene Terephtalate Glycol-modified) using fused-filament-fabrication. The experimental evaluation of this prototype showed a good agreement with the numerical model describing the design. A novel compliant scissor mechanism was obtained in the design process and this mechanism can prove useful in the design of other compliant shape-preserving mechanisms.