In Vivo Based Fluid–Structure Interaction Biomechanics of the Left Anterior Descending Coronary Artery

2021 ◽  
Vol 143 (8) ◽  
Author(s):  
Harry J. Carpenter ◽  
Alireza Gholipour ◽  
Mergen H. Ghayesh ◽  
Anthony C. Zander ◽  
Peter J. Psaltis

Abstract A fluid–structure interaction-based biomechanical model of the entire left anterior descending coronary artery is developed from in vivo imaging via the finite element method in this paper. Included in this investigation is ventricle contraction, three-dimensional motion, all angiographically visible side branches, hyper/viscoelastic artery layers, non-Newtonian and pulsatile blood flow, and the out-of-phase nature of blood velocity and pressure. The fluid–structure interaction model is based on in vivo angiography of an elite athlete's entire left anterior descending coronary artery where the influence of including all alternating side branches and the dynamical contraction of the ventricle is investigated for the first time. Results show the omission of side branches result in a 350% increase in peak wall shear stress and a 54% decrease in von Mises stress. Peak von Mises stress is underestimated by up to 80% when excluding ventricle contraction and further alterations in oscillatory shear indices are seen, which provide an indication of flow reversal and has been linked to atherosclerosis localization. Animations of key results are also provided within a video abstract. We anticipate that this model and results can be used as a basis for our understanding of the interaction between coronary and myocardium biomechanics. It is hoped that further investigations could include the passive and active components of the myocardium to further replicate in vivo mechanics and lead to an understanding of the influence of cardiac abnormalities, such as arrythmia, on coronary biomechanical responses.

Author(s):  
Minyan Yin ◽  
Jun Li ◽  
Liming Song ◽  
Zhenping Feng

The aerodynamic and mechanical performance of the last stage was numerically investigated using three-dimensional Reynolds-Averaged Navier-Stokes (RANS) solution and Finite Element Analysis (FEA) coupled with the one-way and two-way fluid-structure interaction models in this work. The part-span damping snubber and tip damping shroud of the rotor blade and aerodynamic pressure on rotor blade mechanical performance was considered in the one-way model. The two-way fluid-structure interaction model coupled with the mesh deformation technology was conducted to analyze the aerodynamic and mechanical performance of the last stage rotor blade. One-way fluid-structure interaction model numerical results show that the location of nodal maximum displacement moves from leading edge of 85% blade span to the trailing edge of 85% blade span. The position of nodal maximum Von Mises stress is still located at the first tooth upper surface near the leading edge at the blade root of pressure side. The two-way fluid-structure interaction model results show that the variation of static pressure distribution on long blade surface is mostly concentrated at upper region, absolute outflow angle of long blade between the 40% span and 95% span reduces, the location of nodal maximum displacement appears at the trailing edge of 85% blade span. Furthermore, the position of nodal maximum Von Mises stress remains the same and the value decreases compared to the oneway fluid-structure model results.


2016 ◽  
Vol 33 (8) ◽  
pp. 2504-2529 ◽  
Author(s):  
Babak Lotfi ◽  
Bengt Sunden ◽  
Qiu-Wang Wang

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.


Author(s):  
Esfandyar Kouhi ◽  
Yos Morsi

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.


CFD letters ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 115-136
Author(s):  
Hedy Soon Keey Tiew ◽  
Ming Wei Lee ◽  
Wei Shyang Chang ◽  
Mohammad Hafifi Hafiz Ishak ◽  
Farzad Ismail

To achieve high fuel efficiency, vehicles designs are inclined to choose lightweight materials and structures. However, these structures are generally weak, and structural integrity is a common concern. The purpose of this paper is to carry out fluid-structure interaction (FSI) study in one-way coupling analysis on a Shell Eco Marathon (SEM) prototype car which travels in a low-speed range to analyse its structural response. A new set of economical materials is proposed and analysed with the concern on self-fabrication process. The Flax fibre composite is introduced as a part of the proposed material set due to its environmental and economic advantages. The study herein is purely a numerical simulation work as a first approach to design a sustainable SEM prototype car. The fully assembled SEM prototype car was analysed with the proposed materials with ANSYS Workbench in the coupling of the fluid (ANSYS Fluent) and structural solver (ANSYS Mechanical) in a one-way FSI. Even with a thin shell design, the proposed material only experiences minimum deformations. The simulations also reveal that the maximum von-Mises stress experienced, after considered the safety factor, is still several order lower than the yield strength. This study has confirmed that the car design has fulfilled its structural requirements to operate at the design speed.


2012 ◽  
Vol 12 (01) ◽  
pp. 1250003 ◽  
Author(s):  
K. H. J. VAN ASWEGEN ◽  
A. N. SMUTS ◽  
C. SCHEFFER ◽  
H. S. VH. WEICH ◽  
A. F. DOUBELL

Prosthetic aortic valves have been used for the replacement of dysfunctional native aortic valves in humans for more than fifty years. Current prosthetic valves have significant limitations and the development of improved aortic valve prostheses remains an important research focus area. This paper investigates one of the newer additions to the family of replacement valves, namely the stented percutaneous valve. An important design aspect of stented percutaneous valves, is the configuration of the leaflet's attachment to the surrounding stent. There are essentially two possible configurations: The first method is attaching the leaflets in a straight configuration, and the second method is to attach the leaflets in a curved configuration. Finite element models of both configurations were created, and the behavior of these configurations was then studied using a fluid-structure interaction (FSI) simulation. The FSI simulation was validated by means of comparing simulation results to actual measurements from a pulse duplicator using prototype valves of both configurations. The FSI results showed no significant difference between the valves' opening and closing behaviors. The von Mises stress distributions proved to be the largest differentiating and decisive factor between the two valves. The FSI simulations did however show that the leaflets that are attached in the straight configuration form folds that resembles that of the curved configuration as well as the native valve, but to a larger scale. The effect that these folds might have on valve tissue fatigue leaves room for future investigation.


2016 ◽  
Vol 36 (6) ◽  
Author(s):  
Arezoo Khosravi ◽  
Milad Salimi Bani ◽  
Hossein Bahreinizade ◽  
Alireza Karimi

In the present study, three layers of the ascending aorta in respect to the time and space at various blood pressures have been simulated. Two well-known commercial finite element (FE) software have used to be able to provide a range of reliable numerical results while independent on the software type. The radial displacement compared with the time as well as the peripheral stress and von Mises stress of the aorta have calculated. The aorta model was validated using the differential quadrature method (DQM) solution and, then, in order to design functionally graded materials (FGMs) with different heterogeneous indexes for the artificial vessel, two different materials have been employed. Fluid–structure interaction (FSI) simulation has been carried out on the FGM and a natural vessel of the human body. The heterogeneous index defines the variation of the length in a function. The blood pressure was considered to be a function of both the time and location. Finally, the response characteristics of functionally graded biomaterials (FGBMs) models with different values of heterogeneous material parameters were determined and compared with the behaviour of a natural vessel. The results showed a very good agreement between the numerical findings of the FGM materials and that of the natural vessel. The findings of the present study may have implications not only to understand the performance of different FGMs in bearing the stress and deformation in comparison with the natural human vessels, but also to provide information for the biomaterials expert to be able to select a suitable material as an implant for the aorta.


2014 ◽  
Vol 578-579 ◽  
pp. 256-262 ◽  
Author(s):  
Fathallah Elsayed ◽  
Li Li Tong ◽  
Hui Qi ◽  
Mahmoud Helal

Predicting the dynamic response of a floating and submerged structure subjected to underwater explosion is greatly complicated by the explosion of a high explosive, propagation of shock wave, bubble-pulse, complex fluid-structure interaction phenomena and the dynamic behavior of the floating structures. A numerical simulation has been carried out to examine the behavior of elliptical submersible pressure hull to non-contact underwater explosion (UNDEX) and take the effect of bubble-pulse. The finite element package ABAQUS was used to model the UNDEX and the fluid-structure interaction (FSI) phenomena. The pressure wave resulting from an UNDEX was assumed to be a spherical wave. Plastic strain and the time histories of the wet-surface displacement, velocity and von Mises stress are presented. The analytical results are valuable for designing underwater vehicles to resist UNDEX.


2017 ◽  
Vol 9 (2) ◽  
pp. 168781401769121 ◽  
Author(s):  
Ranjitsinha R Gidde ◽  
Prashant M Pawar

Micropumps are the most important components of lab-on-a-chip devices, which are becoming popular recently due to their enormous advantages. Among the different designs of micropumps, the nozzle–diffuser valveless design is the most preferred one due to simplicity in manufacturing. For the simulation of these pumps, the local fluid–structure interaction modeling is important to get the performance accuracy. To capture fluid–structure interaction accurately, an appropriate selection of the fluid as well as the structural modeling approaches are very essential. It is well known that the polydimethylsiloxane materials behave as a viscoelastic material. However, most of the earlier studies on polydimethylsiloxane micropump modeling have considered polydimethylsiloxane as a linear elastic material. In this article, a nozzle–diffuser-based valveless micropump is modeled using a fluid–structure interaction approach along with a linear viscoelastic model for polydimethylsiloxane. The mechanical properties of the polydimethylsiloxane material are experimentally obtained using dynamic mechanical analysis for the range of micropump operating frequencies. These viscoelastic properties of polydimethylsiloxane, with varying proportionate of curing agent, are introduced in the fluid–structure interaction model of micropump using the Kelvin–Voigt model. The results are presented in the form of micropump performance parameters such as diaphragm deflection, von-Mises stresses, swept volume, and fluid flow rate.


Sign in / Sign up

Export Citation Format

Share Document