Fluid Solid Coupling Analysis Of Atherosclerotic Vessels Under The Blood Flow State

Because of the high morbidity and mortality,cardiovascular and cerebrovascular diseases(CCVD)constitute a serious threat to human health and life.Atherosclerosis is commonly found in patients with CCVD.It is helpful to explore the pathogenesis and regulation of CCVD by studying the biomechanical mechanism of atherosclerosis.A large number of studies have shown that the formation and development of atherosclerosis involves many factors,among which hemodynamic factors play an important role in this process.Therefore,it is of great theoretical significance and application value to make a thorough study of the hemodynamic environment by means of numerical simulation.In this dissertation,the finite volume method is used as the basic method.According to the fluid mechanics theory established continuity equation and motion equation of blood.By applying the fluid boundary conditions,fluid solid coupling boundary conditions and related parameters,the STAR CCM+software was used to simulate the pulsatile blood flow in the atherosclerotic artery.Research content mainly includes the following aspects:The3D rigid and elastic models with different degree of local stenosis(25%,50%,75%)were simulated,and compared the effects of different degree of stenosis on blood flow velocity,pressure,wall displacement,circumferential stress and wall shear stress.Through the simulation of different taper angles(?=0.5°??=1°??=2°)of the 3D rigid and elastic models,analyzed the influence of different taper angles on the deformation and stress of the artery wall and the flow field.The changes of artery wall displacement,circumferential stress and wall shear stress in different constitutive parameters n,different thickness h and different diameters D were simulated and analyzed,which calculated in specimens containing 50%stenosis of elastic models.The simulation results indicated that the greater the degree of stenosis,the larger the blood flow velocity and wall shear stress in the throat,where pressure is minimum.Secondary hypertension in the upstream and flow recirculation in the downstream.Blood flow velocity,pressure,wall displacement,circumferential stress and wall shear stress all increased with the increase of taper angle.The change of hemodynamics in rigid model is more severe than that of elastic model.When the structure parameter n and wall thickness h increases or the diameter D decreases,the displacement of the vessel wall and the circumferential stress decrease,while the wall shear stress increases.In this paper,the wall deformation,stress and flow field in the atherosclerotic artery are simulated from several aspects.The simulation results provide hemodynamic mechanism for the formation and development of atherosclerosis,and provide a theoretical basis for clinical diagnosis.