基于ANSYS的生物瓣膜流固耦合力学性能分析

发布时间：2018-04-17 12:47

本文选题：生物瓣膜 + 心脏力学　；参考：《山东大学》2014年硕士论文

【摘要】：心脏为人体血液提供源源不断的动力,一旦其瓣膜发生病症,将会危及人的生命安全。瓣膜置换是治疗风湿性心脏瓣膜病的主要手段。目前应用于临床的瓣膜主要分为机械瓣和生物瓣。生物瓣具有优良的血流动力学性能、不需要终生抗凝、血栓发生堵塞率低以及与心脏瓣膜有关的并发症发生少等优异性,使其在治疗心脏瓣膜病占有率上呈逐年上升的趋势。然而,由于瓣叶的形态、瓣膜材料以及血液的流动状态等因素,使得瓣膜易产生组织钙化、瓣叶撕裂等失效方式,不能够满足临床上对生物瓣膜寿命的较高期望。机械应力是造成生物瓣膜钙化和瓣叶撕裂的主要原因,设计并研制出性能优良、耐久性的生物瓣膜是国内外亟待解决的问题。论文首先以薄膜壳理论和心瓣流体力学理论为依据,利用计算机辅助设计软件PRO/E设计出椭球型面生物瓣膜模型。依据临床数据构建出动脉壁模型,然后利用ANSYS/WORKBENCH得到生物瓣膜与血液的流固耦合模型。基于血管力学和心脏力学,用ALE法推导出瓣叶与血液耦合的基本框架、原理与耦合方程,给出了ALE法在生物瓣膜流固耦合分析的上的可行性以及重要性。为了使模型的受力情况更接近真实环境,采用了临床上生理相关参数。最后,应用有限元分析软件ANSYS/WORKBENCH对所建模型进行有限元分析,得出应力分布结果,分别比较几种不同参数对生物瓣膜力学性能的影响。通过对生物瓣膜力学性能的分析,可以看出,生物瓣膜在工作情况下,其瓣叶上所受的最大等效应力和应力集中出现在瓣叶与瓣架的缝合区域,这与临床资料显示的瓣叶容易主要发生撕裂和组织钙化的病变区域是相符的。通过不同的生物瓣膜瓣叶泊松比对生物瓣膜力学性能的分析,当泊松比为0.3时,其瓣叶上各项主要参数都要优异与所选择的其它组对照数据,其动态力学性能较优。分析不同的弹性模量对生物瓣膜的力学性能显示,当生物瓣膜材料的弹性模量选择为1500Pa时,其动态力学各项性能较优。考虑瓣叶不同厚度对生物瓣膜力学性能的分析显示,当瓣叶的厚度为0.54mm时,其瓣叶各项动态力学性能较优。分析血液入口速度对生物瓣膜力学性能影响时,当入口速度为1m/s时,瓣叶上各项动态力学性能较优,其更好的满足了临床上的要求。通过对生物瓣膜的流固耦合动态分析,得到了不同参数对生物瓣膜力学性能影响,为设计和优化生物瓣膜,提高生物瓣膜耐久性提供重要的基础。本文使用有限元方法对生物瓣膜的流固耦合动态力学性能进行分析,所得到的瓣叶在血液的载荷作用下的应力分布更加真实,是瓣膜设计和分析的重要尝试,为瓣叶的设计、优化和加工提供了重要的参考和实验依据,对评估生物瓣膜的寿命和撕裂有着重要的指导意义。
[Abstract]:Everfount heart to provide power for human blood, once the valve disease, will endanger the safety of human life. Valve replacement is the main method for the treatment of rheumatic heart disease. The clinical application of valve consists of mechanical valve and bioprosthetic valve. The biological valve has excellent hemodynamic performance, does not require life-long anticoagulation the low rate of thrombosis, blockage and associated with heart valve complications less excellent, in the treatment of valvular heart disease share increased year by year. However, because the valve leaf shape, valve material and blood flow condition, the valve is easy to produce tissue calcification, leaflet laceration etc. the failure mode, can not meet the clinical on biovalve life of high expectations. Mechanical stress is a major cause of bioprosthetic heart valve calcification and leaflet laceration, designed and developed the performance Good and durable biological valve is an urgent problem to be solved at home and abroad.
Firstly, with the membrane theory and heart valve fluid mechanics theory, computer aided design software PRO/E to design the surface biovalve ellipsoid model by using computer. On the basis of clinical data to construct out vein wall model, and then use ANSYS/WORKBENCH to get biovalve blood and fluid solid coupling model. Vascular mechanics and cardiac mechanics based on the basic framework for ALE deduced the leaflet and blood coupling, principle and coupling equation, gives the ALE method in fluid solid coupling analysis of bioprosthetic heart valve and the importance of the force. In order to make the model more close to the real environment, the physiological parameters related to clinical application. Finally, the finite element analysis software of ANSYS/WORKBENCH the model of finite element analysis, the stress distribution results, compare different parameters influence on the mechanical properties of several kinds of biological valves.
Through the analysis of biovalve mechanical properties can be seen, biovalve in working condition, the maximum equivalent by the leaflet on stress and stress concentration occurs in the region and valve leaflet suture frame, the lesions and clinical data show Ye Rongyi flap occurred mainly tear and calcification is consistent. Through the analysis of different mechanical properties of bioprosthetic heart valve leaflets with Poisson ratio, when the Poisson ratio is 0.3, the valve on the main parameters are excellent with the choice of the other group data, the dynamic mechanical properties are excellent. Analysis of different elastic modulus on the mechanical properties of biovalve show when the elastic modulus of biovalve material selection for 1500Pa, its dynamic mechanical performance is excellent. Considering the analysis of valve leaf thickness on the mechanical properties of the bioprosthetic heart valve leaflets showed that when the thickness is 0.54mm, the leaflets The dynamic mechanical properties of the better. Analysis of the influence of blood entrance velocity on the mechanical properties of biological valves, when the entrance speed is 1m/s, the leaflets on the dynamic mechanical performance is better and better to meet the clinical requirements. The biovalves FSI dynamic analysis, the effects of different parameters on the biological valve mechanical properties for the design and optimization of biovalve, improve provides an important basis of biological valve durability.
In this paper, using the finite element method of biovalve fluid solid coupling dynamic mechanical performance analysis, the leaflets at the loading of the blood and the stress distribution is more realistic, is an important attempt to valve design and analysis, for the design of leaflets, provide reference and experimental basis to optimization and processing. Has an important guiding significance for the evaluation of bioprosthetic heart valve life and tear.

【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：R318.01

【参考文献】