残余应力对支架放置后血管的力学特性的影响

发布时间：2018-03-01 11:03

本文关键词： 生物力学心血管疾病残余应力有限元模拟血管支架　出处：《上海交通大学》2012年硕士论文　论文类型：学位论文

【摘要】：随着生活水平的提高,心血管疾病的发病率越来越高,已经成为现代社会的沉重负担。支架植入术因其微创伤和高效性,是目前治疗心血管狭窄的主导方法。如何有效的置入支架,以提高治疗的成功率,减小二次狭窄的发生,是当前心血管治疗与研究的重点与热点。在这些涵盖了细胞、组织生物力学和力学生物学研究中,针对血管和支架之间相互作用的研究是基础。而如何结合血管的非线性力学特性,研究支架放置对血管壁应力的影响是本论文研究的重点。本文就以下三个方面进行了研究。1、血管残余应力的数理构建。即使在离体状态下,血管中仍存在着残余应力。将血管沿径向剪开,它会迅速张开,形成一个张开角。本文运用有限元数值模拟与弹性力学半逆解法求解出血管的残余应力。2、血管在体应力模型的数值构建。在血管模型上加载残余应力后,并考虑在体血管所承受的其它载荷,本文进一步建立血管在体状态下的有限元模型。3、血管与支架相互作用的数值研究及分析。本文采用数值模拟研究了正常血管与支架接触过程中,离体状态与在体状态下血管应力分布的差异;在此基础上,我们讨论了病变血管与支架接触过程中,残余应力对于血管应力水平的影响。通过数值和理论分析,本文主要得到了以下结论:1、有限元模拟与弹性力学半逆解法有着较好的一致性。2、血管残余应力的存在的确改善了血管在体应力的分布;同时在数值模拟中对血管进行分层将有助于得到更加真实的计算结果。3、支架植入后,在体条件下血管的应力分布均匀程度要远高于离体条件下血管的应力分布。支架的置入会在很大程度上提高血管的整体应力水平。本文的研究弥补了目前对血管残余应力研究的不足,为优化支架放置,使放置后血管的应力状态得到优化,减少促使二次狭窄病变发生的应力水平给出了力学支持。为支架设计和支架放置方法的评估提供一些参考。
[Abstract]:With the improvement of living standards, the incidence of cardiovascular disease is more and more high, has become a heavy burden on modern society. Stent implantation for its micro trauma and high efficiency, is currently the treatment of cardiovascular stent stenosis leading method. How to effectively, to improve the power of treatment, two reduction of restenosis, is the current focus of cardiovascular research and treatment. In these covers cells, biomechanics and mechanobiology research organization, research on the interaction between stent and vessel is the basis. Combining the nonlinear mechanical characteristics of vascular stent placement, study effects on the vascular wall stress is the focus of this thesis.
In this paper, the following three aspects of the study of.1, the construction of mathematical vascular residual stress. Even in vitro, blood vessels in the residual stress still exist. The vessel along radial cut, it will spread quickly, forming an opening angle. This paper uses the finite element numerical simulation and semi inverse elasticity a method for solving the residual stress of.2, the construct of the stress state of blood vessels in the body. The residual stress loading in the vessel model, and consider other loads in vivo, further establish the finite element model of the blood vessels in the body under the condition of.3, numerical simulation and analysis of the interaction between vessel and stent. Based on the numerical simulation of the normal vessel and stent contact process, in vitro and in vivo vascular status differences of stress distribution; on this basis, we discuss the vascular lesions and stent contact process, residual stress on The effect of the vascular stress level.
Through numerical simulation and theoretical analysis, this paper obtained the following conclusions: 1. The finite element simulation of elastic mechanics and semi inverse method has a good consistency between.2 and vascular the presence of residual stress distribution did improve blood vessels in the body stress; at the same time the results layer will help get more real.3 the blood vessels in the numerical simulation, after stent implantation, in vitro vascular stress distribution uniformity is far higher than that from the stress distribution under the condition of the body. The vascular stent placement improves vascular stress level to a great extent.
This study makes up the lack of research on vascular residual stress, placed in order to optimize the stent, placed after vascular stress state has been optimized to reduce the two stenosis occurred in the stress level is given mechanical support. To provide some reference for support design and evaluation method of placing stents.

【学位授予单位】：上海交通大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：O344.1;R312

【参考文献】