Shape optimization of stress concentration-free lattice for self-expandable Nitinol stent-grafts

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• 作者：Ehsan Masoumi Khalil Abad^a ; ^{ehsan.masoumikhalilabad@mail.mcgill.ca} ; Damiano Pasini^a ; ^{damiano.pasini@mcgill.ca} ; Renzo Cecere^b ; ^{renzo.cecere@muhc.mcgill.ca}
• 关键词：Optimization ; Nitinol ; Stent-graft ; FEM
• 刊名：Journal of Biomechanics
• 出版年：2012
• 期刊代码：144_00219290
• 类别：med
• 出版时间：5 April, 2012
• 卷：45
• 期：6
• 页码：1028-1035
• 文件大小：1428 K

摘要

In a mechanical component, stress-concentration is one of the factors contributing to reduce fatigue life. This paper presents a design methodology based on shape optimization to improve the fatigue safety factor and increase the radial stiffness of Nitinol self-expandable stent-grafts. A planar lattice free of stress concentrators is proposed for the synthesis of a stent with smooth cell shapes. Design optimization is systematically applied to minimize the curvature and reduce the bending strain of the elements defining the lattice cells. A novel cell geometry with improved fatigue life and radial supportive force is introduced for Nitinol self-expandable stent-grafts used for treating abdominal aortic aneurism. A parametric study comparing the optimized stent-graft to recent stent designs demonstrates that the former exhibits a superior anchoring performance and a reduction of the risk of fatigue failure.