A New Way to Simulate the Fluid Structure Interaction between the Bioprosthetic Heart Valve and Blood: FE-SPH Method

2014 ◽  
Vol 472 ◽  
pp. 125-130 ◽  
Author(s):  
Quan Yuan ◽  
Xin Ye
Keyword(s):  
Heart Valve ◽  
Numerical Models ◽  
Fluid Structure Interaction ◽  
Peak Stress ◽  
Bioprosthetic Heart Valve ◽  
Ejection Time ◽  
Sph Method ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Von Mises

The object of this study is to utilize FE-SPH method to simulate the dynamic behavior of bioprosthetic heart valve during systole. Two kind of bioprosthetic heart valve numerical models are designed based on membrane theory, and they are represented by FE mesh, the blood is modelled as SPH particles. The interaction between the blood and bioprosthetic heart valve is carried out with contact algorithms. Results show that: when the valve leaflets are opening, compared with that of spherical valve, the stress and strain states of cylindrical valve are unstable, and the peak Von Mises is also higher, which high peak stress and its instability may induce the fatigue of valve. The valve opening time of columnar valve leaflets is longer than that of spherical ones, which reduces the blood ejection time. Above results indicate that spherical valve is superior to cylindrical valve. The FE-SPH method is capable of simulating the fluid structure interaction between the bioprosthetic heart valve and blood during the systole.

Fluid Structure Interaction Analysis of Stentless Bio-Prosthetic Aortic Heart Valve in Sinus of Valsalva

2010 ◽  
Author(s):  
Esfandyar Kouhi ◽  
Yos Morsi
Keyword(s):  
Blood Flow ◽  
Heart Valve ◽  
Interaction Analysis ◽  
Fluid Structure Interaction ◽  
Fluid Pressure ◽  
Von Mises Stress ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Aortic Heart Valve ◽  
Von Mises

In this paper the fluid structure interaction in stentless aortic heart valve during acceleration phase was performed successfully using the commercial ANSYS/CFX package. The aim is to provide unidirectional coupling FSI analysis of physiological blood flow within an anatomically corrected numerical model of stentless aortic valve. Pulsatile, Newtonian, and turbulent blood flow rheology at aortic level was applied to fluid domain. The proposed structural prosthesis had a novel multi thickness leaflet design decreased from aortic root down to free age surface. An appropriate interpolation scheme used to import the fluid pressure on the structure at their interface. The prosthesis deformations over the acceleration time showed bending dominant characteristic at early stages of the cardiac cycle. More stretching and flattening observed in the rest of the times steps. The multi axial Von Mises stress data analysis was validated with experimental data which confirmed the initial design of the prosthesis.

Computational Modeling for Fluid–Structure Interaction of Bioprosthetic Heart Valve with Different Suture Density: Comparison with Dynamic Structure Simulation

2017 ◽  
Vol 31 (11) ◽  
pp. 1757007 ◽  
Author(s):  
Z. C. Wang ◽  
Q. Yuan ◽  
H. W. Zhu ◽  
B. S. Shen ◽  
D. Tang
Keyword(s):  
Computational Modeling ◽  
Principal Stress ◽  
Heart Valve ◽  
Fluid Structure Interaction ◽  
Dynamic Structure ◽  
Left Ventricular ◽  
Bioprosthetic Heart Valve ◽  
Fluid Structure ◽  
Maximum Deformation ◽  
Structure Interaction

In this paper, a parametric geometry model based on elliptic and conic surfaces was developed for bioprosthetic heart valve (BHV) simulation. The valve material was modeled by a hyperelastic nonlinear anisotropic solid model. Different suture densities could be substituted by various bonded points between artery vessel and the leaflets as boundary conditions in the computational modeling. Besides these two assumptions that dynamic structure (DS) and fluid–structure interaction (FSI) both shared, the latter need incompressible viscous Newton fluid model to depict bloodstream passing through the BHV. Immersed boundary (IB) method was introduced to solve the FSI simulation. In addition, the DS analysis applied transvalvular pressure on the valve while FSI had left ventricular pressure on fluid inlet as initials. There was inconsistency between the moments of the maximum deformation and the maximum loading in both simulations. Although a similar trend of deformation lagging the load was viewed, the extent of delay in FSI was much smaller compared with that in DS simulation. The deformed profiles in cross-sectional views were shown in one picture to illustrate different dynamic responses caused by distinct assumptions. Percent of open area at the moments when the maximum deformation occurred was defined to show which calculation achieved better approximation for precise hemodynamics. Fixed point was given as boundaries between BHV and artery in the modeling part. Calculations showed that the more the fixed points in this bonded contact, the lower the principal stress was. The maximum shear stress showed a different trend. It had a different trend. Stress concentration in the conjunction area made it high-risk to be teared. Different suture densities had significant impaction in FSI simulations. With that analysis our work achieved a more comprehensive simulation to describe true hemodynamics of a BHV implanted in artery. The artery vessel had particular dynamic response under such assumptions, gradient existed in the maximum principal stress distribution diagram, from inner wall through which blood passing to the outer wall. Results showed a large suture density was suggested in BHV implantation.

3D fluid-structure interaction (FSI) simulation of new type vortex generators in smooth wavy fin-and-elliptical tube heat exchanger

2016 ◽  
Vol 33 (8) ◽  
pp. 2504-2529 ◽  
Author(s):  
Babak Lotfi ◽  
Bengt Sunden ◽  
Qiu-Wang Wang
Keyword(s):  
Heat Exchanger ◽  
Mechanical Behavior ◽  
Elastic Strain ◽  
Fluid Structure Interaction ◽  
Vortex Generators ◽  
Von Mises Stress ◽  
Fluid Structure ◽  
Content Type ◽  
Structure Interaction ◽  
Von Mises

Purpose The purpose of this paper is to investigate the numerical fluid-structure interaction (FSI) framework for the simulations of mechanical behavior of new vortex generators (VGs) in smooth wavy fin-and-elliptical tube (SWFET) heat exchanger using the ANSYS MFX Multi-field® solver. Design/methodology/approach A three-dimensional FSI approach is proposed in this paper to provide better understanding of the performance of the VG structures in SWFET heat exchangers associated with the alloy material properties and geometric factors. The Reynolds-averaged Navier-Stokes equations with shear stress transport turbulence model are applied for modeling of the turbulent flow in SWFET heat exchanger and the linear elastic Cauchy-Navier model is solved for the structural von Mises stress and elastic strain analysis in the VGs region. Findings Parametric studies conducted in the course of this research successfully identified illustrate that the maximum magnitude of von Mises stress and elastic strain occurs at the root of the VGs and depends on geometrical parameters and material types. These results reveal that the titanium alloy VGs shows a slightly higher strength and lower elastic strain compared to the aluminum alloy VGs. Originality/value This paper is one of the first in the literature that provides original information mechanical behavior of a SWFET heat exchanger model with new VGs in the field of FSI coupling technique.

scholarly journals Image-Guided Fluid-Structure Interaction Simulation of Transvalvular Hemodynamics: Quantifying the Effects of Varying Aortic Valve Leaflet Thickness

Fluids ◽  
2019 ◽  
Vol 4 (3) ◽  
pp. 119 ◽  
Author(s):  
Anvar Gilmanov ◽  
Alexander Barker ◽  
Henryk Stolarski ◽  
Fotis Sotiropoulos
Keyword(s):  
Blood Flow ◽  
Aortic Valve ◽  
Heart Valve ◽  
Fluid Structure Interaction ◽  
Maximum Velocity ◽  
Patient Specific ◽  
Hemodynamic Parameters ◽  
Orifice Area ◽  
Fluid Structure ◽  
Structure Interaction

When flow-induced forces are altered at the blood vessel, maladaptive remodeling can occur. One reason such remodeling may occur has to do with the abnormal functioning of the aortic heart valve due to disease, calcification, injury, or an improperly-designed prosthetic valve, which restricts the opening of the valve leaflets and drastically alters the hemodynamics in the ascending aorta. While the specifics underlying the fundamental mechanisms leading to changes in heart valve function may differ from one cause to another, one common and important change is in leaflet stiffness and/or mass. Here, we examine the link between valve stiffness and mass and the hemodynamic environment in aorta by coupling magnetic resonance imaging (MRI) with high-resolution fluid–structure interaction (FSI) computational fluid dynamics to simulate blood flow in a patient-specific model. The thoracic aorta and a native aortic valve were re-constructed in the FSI model from the MRI data and used for the simulations. The effect of valve stiffness and mass is parametrically investigated by varying the thickness (h) of the leaflets (h = 0.6, 2, 4 mm). The FSI simulations were designed to investigate systematically progressively higher levels of valve stiffness by increasing valve thickness and quantifying hemodynamic parameters known to be linked to aortopathy and valve disease. The computed results reveal dramatic differences in all hemodynamic parameters: (1) the geometric orifice area (GOA), (2) the maximum velocity V max of the jet passing through the aortic orifice area, (3) the rate of energy dissipation E ˙ diss ( t ) , (4) the total loss of energy E diss , (5) the kinetic energy of the blood flow E kin ( t ) , and (6) the average magnitude of vorticity Ω a ( t ) , illustrating the change in hemodynamics that occur due to the presence of aortic valve stenosis.

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