Mechanism-driven recoil performance in auxetic structures: Numerical modeling and additive manufacturing verification

This study presents a novel auxetic mechanical structure (AMS) designed to reduce recoil in stents application. Building upon a peanut-shaped auxetic lattice with a negative Poisson’s ratio, various single- and double-layer AMS configurations were developed by integrating friction-based (clamp, tubular, elliptical interlocking) and locking-based (locking, ratchet) mechanisms. Finite element analysis (FEA) and additive-manufactured prototypes were employed to evaluate mechanical performance, focusing on recoil mitigation, expansion uniformity, and structural integrity. Results demonstrated that locking-based mechanisms significantly improve recoil resistance, reducing recoil to 3.9% in the single-layer locking design and 5.4% in the double-layer ratchet design, compared to 100% recoil in unmodified structures. Friction-based mechanisms provide moderate improvements but require optimization of clamping force and contact area. Despite minor increases in relative density, AMS designs maintain the auxetic response and expand effective surface area, advantageous for drug delivery. Overall, the AMS approach provides a robust and adaptable design strategy for reducing recoil on auxetic structure. However, further optimization and validation across different auxetic geometries and materials are required to enhance clinical applicability.