镍钛合金冠脉支架纵向柔顺性数值分析

Numerical analysis on longitudinal flexibility of a Ni Ti coronary stent

目的利用有限元方法分析自主设计镍钛合金冠脉支架的结构特征与纵向柔顺性的关系。方法通过Soildworks设计一种新型支架的几何模型,运用Hypermesh、MATLAB及ABAQUS软件构建出支架的有限元模型,在ABAQUS中对支架一个结构周期内的9个弯曲方向上分别施加转角位移,使支架保持纯弯曲状态。结果支架柔顺性在自接触前差异性不明显;当自接触发生后,支架的柔顺性表现出明显的各向异性,同时支架在平面内的纯弯曲载荷作用下发生弯曲变形,并伴随着平面外的偏转及围绕自身轴线的扭转变形。结论支架的结构特征决定了其弯曲行为,连接体的螺旋和自接触使支架的柔顺性始终表现出各向异性,为支架在临床上的应用提供科学指导。

Objective To analyze the relationship between structure characteristics and longitudinal flexibility of the self-designed Ni Ti 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.