Berti Francesca, Wang Pei-Jiang, Spagnoli Andrea, Pennati Giancarlo, Migliavacca Francesco, Edelman Elazer R, Petrini Lorenza
Laboratory of Biological Structure Mechanics, Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133, Milano, Italy; Biomedical Engineering Center, Institute for Medical Engineering & Science, Massachusetts Institute of Technology, Cambridge, MA, USA.
Biomedical Engineering Center, Institute for Medical Engineering & Science, Massachusetts Institute of Technology, Cambridge, MA, USA.
J Mech Behav Biomed Mater. 2021 Jan;113:104142. doi: 10.1016/j.jmbbm.2020.104142. Epub 2020 Oct 18.
Ni-Ti stents fatigue strength assessment requires a multi-factorial complex integration of applied loads, material and design and is of increasing interest. In this work, a coupled experimental-numerical method for the multi-axial fatigue strength assessment is proposed and verified for two different stent geometries that resemble commercial products. Particular attention was paid to the identification of the material fatigue limit curve. The common approach for the Ni-Ti stents fatigue assessment based on the von Mises yield criterion was proven unsuitable for a realistic fatigue strength assessment. On the other hand, critical plane-based criteria were more representative of the experimental outcomes regardless of stent design.
镍钛合金支架的疲劳强度评估需要对施加的载荷、材料和设计进行多因素的复杂整合，并且越来越受到关注。在这项工作中，提出了一种用于多轴疲劳强度评估的实验与数值相结合的方法，并针对两种类似于商业产品的不同支架几何形状进行了验证。特别关注了材料疲劳极限曲线的识别。事实证明，基于冯·米塞斯屈服准则的镍钛合金支架疲劳评估常用方法不适用于实际的疲劳强度评估。另一方面，无论支架设计如何，基于临界平面的准则更能代表实验结果。
