Salemizadeh Parizi Fatemeh, Mehrabi Reza, Karamooz-Ravari Mohammad Reza
Department of Mechanical Engineering, Vali-e-Asr University of Rafsanjan, Rafsanjan, Iran.
Dynamic and Smart Systems Laboratory, Mechanical, Industrial and Manufacturing Engineering Department (MIME), University of Toledo, Toledo, OH, USA.
Proc Inst Mech Eng H. 2019 Oct;233(10):1042-1050. doi: 10.1177/0954411919865404. Epub 2019 Jul 28.
Transcatheter aortic valve implantation is a minimally invasive treatment for severe symptomatic aortic valve stenosis. Nitinol stents are proposed for aortic stenosis patients at high risk. In the present study, at different implantation depths in the aortic valve, the crimping and performance of Nitinol stents are investigated. To do so, a constitutive model based on Microplane theory is utilized and implemented through the finite element to express the constitutive characteristics of Nitinol. The self-expanding stent made of NiTi is designed and simulated using the finite element method. To validate the developed model, the obtained results using beam and solid finite element models are compared with those reported in the literature. Superelastic behavior as well as shape memory effect of the Nitinol stent is studied during crimping and deployment. The simulated results show that the produced radial force increases by increasing the implantation depth in a cardiac cycle.
经导管主动脉瓣植入术是一种针对严重症状性主动脉瓣狭窄的微创治疗方法。镍钛诺支架被推荐用于高危主动脉狭窄患者。在本研究中，研究了镍钛诺支架在主动脉瓣不同植入深度下的压握情况和性能。为此，利用基于微平面理论的本构模型，并通过有限元方法来实现，以表达镍钛诺的本构特性。采用有限元方法对由镍钛合金制成的自膨胀支架进行设计和模拟。为验证所开发的模型，将使用梁和实体有限元模型获得的结果与文献报道的结果进行比较。研究了镍钛诺支架在压握和展开过程中的超弹性行为以及形状记忆效应。模拟结果表明，在心动周期中，随着植入深度的增加，产生的径向力会增大。
