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The state of stress concentration in a concave-convex self-expanding bracket with a structure that has a negative Poisson ratio was studied using NiTi UMAT program. It has been found that the support performance of the concave and convex bracket changes completely with the variation in the number of units (Nc) and the angle (θ) between the inclined bar and the horizontal direction of the support ring. The change in the axial distance of the support is primarily influenced by the parameters h/l and θ, and it exhibits a negative correlation. The dilation rate of a concave-convex stent in a diseased femoral artery can reach 90.3%, which is generally higher than that of existing self-dilation medical stents. The concave-convex stent can achieve uniform expansion when working in the femoral artery, thereby avoiding the issue of a narrow middle and wide ends. The Goodman fatigue curve and fatigue factor were evaluated, meeting the national requirements for medical stents.