Mechanical behaviour modelling of balloon-expandable stents
Mechanical behaviour modelling of balloon-expandable stents
复制标题
DOI：
10.1016/s0021-9290(00)00098-1
复制
发表时间：
2000-11-01
影响因子：
2.4
通讯作者：
Cochelin, B
中科院分区：
文献类型：
--
作者：
Dumoulin, C;Cochelin, B
人工血管内支架是通过血管内途径放置的小支柱，以恢复血管的管腔和血流状态。本工作的目的是为用有限元方法评价和表征球囊可膨胀支架的某些力学性能提供模型。在这里，我们介绍了一种金属管状外周假体的结果：P308 Palmaz支架。我们将重点放在与结构扩张及其长期行为相关的机制上。为了确定扩张后支架的形状并评估这种转变后支架壁上的应力和应变场，我们建立了几个模型。它们告诉我们膨胀时的缩短率，径向和纵向后坐的程度，以及结构的弱点。各种不同的方法，其复杂程度不同，然后试图展示导致支架在外部压力下破碎的主要因素。此外，还研究了该临界压力对几何缺陷的敏感性。最后，由于这种材料是终身植入的，我们测试了支架的疲劳寿命。除了安全方面的考虑外，这种类型的表征提供了通常很难通过实验获得的机械性能。如果它可用于各种支架，这些信息可以用来选择合适的假体FBR特定应用。此外，面对从业者的观察，他们可能会更好地理解特定设计的成功或失败，并致力于产品优化。(C)2000爱思唯尔科学有限公司。保留所有权利。
Endoprostheses are small struts placed by intravascular way to restore the vascular lumen and flow conditions. The purpose of this work is to provide models for evaluation and characterisation of some mechanical properties of a balloon-expandable stent by using the finite element method. Here we present the results for a metallic tubular peripheral prosthesis: the P308 Palmaz stent. We focus on the mechanisms linked to the structure expansion and its long-term behaviour. Several models are constructed in order to determine the stent shape after dilation and to assess the stress and strain fields in its wall due to this transformation. They inform us about the shortening percentage on expansion, degrees of radial and longitudinal recoil, and weaknesses of the structure. Various methods, differing in their levels of complexity, are then attempted to exhibit the predominant factors responsible for the crushing of a stent under external pressure. Moreover, the sensitivity of this critical pressure to geometric imperfections is studied. Lastly, since this kind of material is implanted for a lifetime, we test the stent with regard to fatigue life. Beyond safety considerations, this type of characterisation provides mechanical properties that are often difficult to obtain by experiments. If it was available for various stents, such information could be used to choose the appropriate prosthesis fbr specific applications. Moreover, confronted with observations from practitioners, they might lead to a better understanding of the failure or success of a particular design and to work on the product optimisation. (C) 2000 Elsevier Science Ltd. All rights reserved.