Additive manufacturing has enabled the fabrication of lightweight complex metamaterials that possess high energy absorption and impact resistance properties. Stents, a typical 3D auxetic material, have significant self-expanding behavior, and their mechanical properties can be finely tuned over a wide range. In this study, we systematically analyzed three distinctive elastic-plastic regions using experimental, numerical simulations, and theoretical analysis, focusing on investigating the energy absorption capability of a designed structure by varying tessellated unit cell numbers in two section views in X- and Y-direction. Two batches of 5 specimens each were 3D printed using FDM techniques. The results showed that designing a self-expanding stent with innovative capabilities was possible, with the yield stress ranging between 1.5 MPa and 2.0 MPa and extended effective elastic moduli derived from the deformation mode of tessellated unit cells. The maximum energy absorption for all structures ranged between 7.1J and 18J, with similar capabilities observed for the designed stents. However, increasing unit cells along the X-direction resulted in a significant increase in SEA, while the Y-direction remained unchanged. Therefore, these structures have a significant influence on areas requiring energy absorption. In addition, they are the ideal class of energy absorbers for cushioning applications. Furthermore, their energy-absorption capacity can be easily tailored to meet specific end-use requirements by varying their structural parameters using unit cell tessellation.
Keywords: Additive manufacturing; Auxetic; Energy absorption; FDM; Stents; Tessellated unit cell.
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