Design and Mechanical Performance of a Double-Braided, Additively Manufactured Stent with Geometry-Controlled Expansion

The design of next-generation biomedical implants is shifting toward architected materials, where mechanical function emerges from geometry rather than homogeneous material response. This principle is realized here through a double-braided, additively manufactured stent, designed as a deployable cylindrical metamaterial. Fabricated in 316 L stainless steel via laser powder bed fusion, its interlaced helical lattice is designed to transform under load through topological reconfiguration. Nonlinear finite element analysis, integrating contact mechanics and elastoplasticity, reveals that controlled radial expansion exceeding 50 percent is achieved via structural kinematics, localizing plastic deformation to discrete nodal hinges. The deployed structure retains high radial stiffness and responds elastically under physiological pressures, with stress amplitudes from pulsatile loading remaining well within the infinite-fatigue-life regime of the material. Experimental radial compression of a printed prototype corroborates the predicted mechanical behavior. This study demonstrates that in stent design, performance can be encoded into geometry, thereby decoupling deployment from in-service function and establishing a new framework for patient-specific, mechanics-driven implant engineering.