Dynamic Analysis Of The Fluid-Solid Coupling Model Based On Atherosclerosis

The rupture of the atherosclerotic plaque is the main trigger of acute cardiovas-cular events,there have not been reasonable explanation about the mechanics of the rupture. This paper constructed a fluid structure interaction model to describe the stress on the atherosclerotic plaque using the fluid dynamics and solid mechanics theory, and research on the stress distribution of the atherosclerotic plaque through numerical simu-lations using software Comsol Multiphysics in order to provide some references to analyze the mechanic of the rupture of the atherosclerotic plaque.The blood is supposed to be a Newtonian fluid and the atherosclerotic plaque is made up of a lipid kernel and a fibrous cap, both of which are viewed as linear materials. Through numerical simulation, we analyze the influences that the property, geometry size of the atherosclerotic plaque and the velocity of the flood play on the normal stress and shearing stress of fibrous cap.This paper are divided into four chapters.Chapter1introduce the research background, including the statement of the mechan-ics of the rupture and simple introduction of simulation software Comsol Multiphyics.Chapter2construct a two-dimensional fluid structure interaction model describing the dynamics process of the atherosclerotic plaque in the vascular. After plenty of numer-ical simulations we get some conclusions about stress distribution and shearing stress on the fibrous cap’s outside surface, pressure differences between inside and outside surface of the cap. The first one is that the property of the fibrous cap and lipid kernel such as the Young’s modulus and Possion ratio play distinct roles on the pressure differences and stress distribution while almost have no effect on the shearing stress. The pressure differences will become weaker as the fibrous cap’s Young’s modulus and Possion ratio get more close to the lipid kernel’s. If the Young’ modulus of fibrous cap is greater than lipid kernel’s, the stress of the plaque usually distribute on the cap; on the other side, if the Young’ modulus of fibrous cap is less than lipid kernel’s, the stress usually distribute on the lipid kernel and Possion’s ratio have a reverse effect to stress distribution. The second one locates on that the geometry size, includes the thickness of the fibrous cap and the ratio of length and height of the plaque, affect both the pressure differences and shearing stress while have no effect to stress distribution of the fibrous cap.As the ratio of height and length of the plaque increases, the pressure differences and shear stress will become fierce. The last conclusion lies on that the velocity of blood also plays an important role to stress on the plaque. Both of the pressure differences and shearing become larger as the velocity become faster.Chapter3focus on the three-dimensional fluid structure interaction model, research-ing on the stress on the plaque. The result indicate that the effect that the Young’s modu-lus of the plaque, geometry model and velocity of the blood have on the pressure difference and shearing stress are similar to two dimensional case. Differences lie on that if the ratio of Possion’s ratio increase, the pressure difference and shearing stress will increase too. Further more the value of the shearing stress is so great that no one can ignore it when analyze the mechanics of the rupture of the atherosclerotic plaque.Chapter4gives the main conclusion of the paper.