Research On Coronary Stent Structure Based On Elastoplastic Mechanics And Fluid-solid Coupling

According to the statistics of the world health organization,cardiovascular disease is a kind of high risk disease that seriously threatens human health.The number of people dying of cardiovascular disease in the world is as high as 15 million every year,ranking the first among all kinds of causes of death.Coronary heart disease is the number one cause of cardiovascular disease.When coronary artery stents are transplanted into blocked or closed blood vessels,the balloon and the stent perform free dilation together to support the stenosis of the diseased blood vessels,but there is also the phenomenon of stent restenosis.Therefore,through numerical simulation and fluid-solid coupling analysis,we can clearly understand the situation after stent implantation into human blood vessels,from which we can understand the mechanical behavior and deformation behavior of the stent.This plays an important role in preventing restenosis of stents.Firstly,we discussed the development process of interventional therapy of coronary stents and the development process of stents at home and abroad,analyzed and coMPared the characteristics of different stents and drugs,discussed the development status and future trend,and then proposed the research content of this paper.Secondly,the basic theory of coronary stent free expansion and fluid-solid coupling is discussed.In the first stage,according to the interaction between balloon and coronary stent,the highly nonlinear problem of stent was determined,and the free expansion simulation was analyzed by finite element theory.As for the bracket itself,the yield criterion of material is discussed and coMPared from two aspectsincrement theory and total quantity theory.In the second stage,the single fluid mechanics governing equation,single solid mechanics governing equation,fluid-solid coupling governing equation and solid-solid coupling governing equation involved in the fluid-solid coupling problem of blood vessel,blood and coronary artery stent are discussed.Thirdly,through the PRO/E to build up a balloon and the 3 d model of coronary stents,using the Workbench Transient Structura(ANSYS)module to carry on the numerical simulation,respectively on the balloon,plate,blood vessels,support for the related definitions,and the whole model in the simulation to set corresponding meshing and boundary conditions,the coupling numerical analysis,through the study of the definition of load analysis and set up the model of relationship between coronary stent deformation condition,draw coronary stents in the free expansion had experienced two stages of stress and strain distribution nephogram.Finally,the problem of fluid-solid coupling generated during the service period after coronary artery stent implantation of diseased vessels was simulated.On the basis of building a three-dimensional model,the material definition,mesh division and boundary conditions of bi-directional fluid-solid coupling were set up.Transient Structural module and Fluent Flow module in Workbench were used for simulation analysis,and finally the blood Flow,vascular deformation and coronary stent stress analysis graph were obtained.The analysis and research in this paper will help stent research institutions to design more outstanding stent,and make new contributions to the development of cardiovascular stent technology and the treatment of stent restenosis.