RESUMO
Objective To analyze the relationship between structure characteristics and longitudinal flexibility of the self-designed NiTi coronary stents by using finite element method. Methods A new type of stent geometric model was designed with the CAD software Soildworks, and then the finite element stent model was established with Hypermesh, MATLAB and ABAQUS software. In ABAQUS, the angular displacement loads were applied on the stent in 9 bending directions within one structural cycle to maintain the stent in a pure bending state. Results The stent flexibility appeared no significant difference before the self-contact occurred, while it showed obvious anisotropy after the self-contact occurred. In addition, the bending deformation occurred under in-plane pure bending loads, accompanied with the out-of-plane deflection and torsion deformation around the axis. Conclusions The bending behavior of the stent is determined by its structural characteristics, and the stent always shows anisotropic flexibility due to its spiral arrangement of the connecting body and self-contact, which will provide a scientific guidance for clinical application of the stent.