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A fluid-structure interaction model of the internal carotid and ophthalmic arteries for the noninvasive intracranial pressure measurement method

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COMPUTERS IN BIOLOGY AND MEDICINE 2017年 84卷 79-88页

作者： Misiulis, Edgaras Dziugys, Algis Navakas, Robertas Striugas, Nerijus Lithuanian Energy Inst Lab Combust Proc Breslaujos St 3 LT-44403 Kaunas Lithuania

Accurate and clinically safe measurements of intracranial pressure (ICP) are crucial for secondary brain damage prevention. There are two methods of ICP measurement: invasive and noninvasive. Invasive methods are clinically unsafe;therefore, safer noninvasive methods are being developed. One of the noninvasive ICP measurement methods implements the balance principle, which assumes that if the velocity of blood flow in both ophthalmic artery segments - the intracranial (IOA) and extracranial (EOA) - is equal, then the acting ICP on the IOA and the external pressure (Pe) on the EOA are also equal. To investigate the assumption of the balance principle, a generalized computational model incorporating a fluid-structure interaction (FSI) module was created and used to simulate noninvasive ICP measurement by accounting for the time-dependent behavior of the elastic internal carotid (ICA) and ophthalmic (OA) arteries and their interaction with pulsatile blood flow. It was found that the extra balance pressure term, which incorporates the hydrodynamic pressure drop between measurement points, must be added into the balance equation, and the corrections on a difference between the velocity of blood flow in the IOA and EOA must be made, due to a difference in the blood flow rate.

关键词： Computational fluid dynamics Hemodynamic Ophthalmic artery fluid-structure interaction Intracranial pressure Noninvasive method

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Fast fluid-structure interaction simulations using a displacement-based finite element model equipped with an explicit streamline integration prediction

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COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING 2017年 315卷 1080-1097页

作者： Ryzhakov, P. B. Marti, J. Idelsohn, S. R. Onate, E. CIMNE Gran Capitan S-N Barcelona 08034 Spain Univ Politecn Cataluna Barcelona Spain ICREA Barcelona Spain

We propose here a displacement-based updated Lagrangian fluid model developed to facilitate a monolithic coupling with a wide range of structural elements described in terms of displacements. The novelty of the model consists in the use of the explicit streamline integration for predicting the end-of-step configuration of the fluid domain. It is shown that this prediction considerably alleviates the time step size restrictions faced by the former Lagrangian models due to the possibility of an element inversion within one time step. The method is validated and compared with conventional approaches using three numerical examples. Time step size and corresponding Courant numbers leading to optimal behavior in terms of computational efficiency are identified. (C) 2016 Elsevier B.V. All rights reserved.

关键词： Incompressible flows Navier-Stokes fluid-structure interaction Particle finite element method Lagrangian Coupled problems

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Investigation on the fluid-structure interaction effect of an aerostatic spindle and the influence of structural dimensions on its performance

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PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART J-JOURNAL OF ENGINEERING TRIBOLOGY 2017年第11期231卷 1434-1440页

作者： Lu, Lihua Gao, Qiang Chen, Wanqun Liu, Liang Wang, Guanglin Harbin Inst Technol Sch Mechatron Engn POB 413 92 West Dazhi St Harbin Heilongjiang Peoples R China

The performances of aerostatic spindle are highly affected by the fluid-structure interaction between air film and solid structure. This paper proposes a comprehensive two-way fluid-structure interaction model to analyze the fluid-structure interaction effect of an aerostatic spindle. The structure deformation induced by air film pressure is considered to predict the actual performance of aerostatic spindle. Furthermore, to provide theoretical basis for the structure parameters design, the influence of structural dimensions (such as the thickness of thrust plate) on its performance is investigated, and optimal structural parameters are acquired. The stiffness of aerostatic spindle with varying thrust plate thickness is tested to verify the reliability of simulation results.

关键词： Aerostatic spindle stiffness fluid-structure interaction ultra-precision machining optimization

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Numerical study of rogue wave overtopping with a fully-coupled fluid-structure interaction model

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OCEAN ENGINEERING 2017年第Jun.1期137卷 48-58页

作者： Hu, Zhe Tang, Wenyong Xue, Hongxiang Zhang, Xiaoying Wang, Kunpeng Shanghai Jiao Tong Univ State Key Lab Ocean Engn Shanghai 200240 Peoples R China Collaborat Innovat Ctr Adv Ship & Deep Sea Explor Shanghai 200240 Peoples R China Jimei Univ Key Lab Ships & Ocean Engn Fujian Prov Xiamen 361021 Peoples R China Jiangsu Univ Sci & Technol Sch Naval Architecture & Ocean Engn Zhenjiang 212003 Peoples R China

For decades, researchers have been devoting efforts to revealing the physical mechanisms of rogue waves. However, research works on the interaction between rogue waves and marine structures, especially those which take into account hydroelastic effects are still not adequate (due to the fact that the wave-breaking, overturning and slamming phenomena are complex especially when hydroelasticity is considered as well as the nonlinearity of rogue waves). In this paper, the nonlinear rogue-wave overtopping phenomenon is simulated in a numerical wave tank. The simulation results are compared against the theoretical solution predicted by the dam-breaking model. Hydroelastic effects are considered by applying a fully-coupled fluid-structure interaction model. The vibration of the elastic deck is analyzed and compared against the one obtained without considering hydroelasticity. Green water events, caused by a rogue wave and a regular wave respectively, are compared to reveal the special features of rogue-wave-induced overtopping. It is found that hydroelastic effects lead to the local vibration of the deck, lower vibration frequencies through introducing the added mass effect, and make the deck deformation larger at certain moments. It is also found that green water induced by rogue waves shows asymmetry and unregularity in comparison with that induced by regular waves.

关键词： Nonlinear rogue wave Wave overtopping fluid-structure interaction Hydroelastic vibration Dam-breaking model

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Immersogeometric cardiovascular fluid-structure interaction analysis with divergence-conforming B-splines

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COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING 2017年 314卷 408-472页

作者： Kamensky, David Hsu, Ming-Chen Yu, Yue Evans, John A. Sacks, Michael S. Hughes, Thomas J. R. Univ Texas Austin Inst Computat Engn & Sci Ctr Cardiovasc Simulat 201 East 24th StStop C0200 Austin TX 78712 USA Iowa State Univ Dept Mech Engn 2025 Black Engn Ames IA 50011 USA Lehigh Univ Dept Math Christmas Saucon Hall14 E Packer Ave Bethlehem PA 18015 USA Univ Colorado Dept Aerosp Engn Sci 429 UCB Boulder CO 80309 USA

This paper uses a divergence-conforming B-spline fluid discretization to address the long-standing issue of poor mass conservation in immersed methods for computational fluid structure interaction (FSI) that represent the influence of the structure as a forcing term in the fluid subproblem. We focus, in particular, on the immersogeometric method developed in our earlier work, analyze its convergence for linear model problems, then apply it to FSI analysis of heart valves, using divergence-conforming B-splines to discretize the fluid subproblem. Poor mass conservation can manifest as effective leakage of fluid through thin solid barriers. This leakage disrupts the qualitative behavior of FSI systems such as heart valves, which exist specifically to block flow. Divergence-conforming discretizations can enforce mass conservation exactly, avoiding this problem. To demonstrate the practical utility of immersogeometric FSI analysis with divergence-conforming B-splines, we use the methods described in this paper to construct and evaluate a computational model of an in vitro experiment that pumps water through an artificial valve. (C) 2016 Elsevier B.V. All rights reserved.

关键词： fluid-structure interaction Bioprosthetic heart valve Immersogeometric analysis Isogeometric analysis Divergence-conforming B-splines Immersed boundary method

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A non-staggered coupling of finite element and lattice Boltzmann methods via an immersed boundary scheme for fluid-structure interaction

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COMPUTERS & fluidS 2017年 143卷 90-102页

作者： Li, Zhe Favier, Julien Ecole Cent Nantes UMR CNRS LHEEA Lab Nantes France Aix Marseille Univ CNRS Cent Marseille UMR 7340 M2P2 Marseille France

The paper presents a numerical framework for the coupling of finite element and lattice Boltzmann methods for transient problems involving fluid-structure interaction. The solid structure is discretized with the finite element method and integrated in time with the explicit Newmark scheme. The lattice Boltzmann method is used for the simulation of single-component weakly-compressible fluid flows. The two numerical methods are coupled via a direct-forcing immersed boundary method in a non-staggered way. Without subiteration within each time-step, the proposed method can ensure the synchronization of the time integrations, and thus the strong coupling of both subdomains by resolving a linear system of coupling equations at each time-step. Hence the energy transfer at the fluid-solid interface is correct, i.e. neither energy dissipation nor energy injection will occur at the interface, which can retain the numerical stability. A well-known fluid-structure interaction test case is adopted to validate the proposed coupling method. It is shown that the stability of the used numerical schemes can be preserved and a good agreement is found with the reference results. (C) 2016 Elsevier Ltd. All rights reserved.

关键词： Finite element method Lattice Boltzmann method Immersed boundary method fluid-structure interaction Interface-energy-conserving

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Dynamic characteristics of the nozzle opening pressure based on the fluid-structure interaction for a double-solenoid-valve fuel injection system

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PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART D-JOURNAL OF AUTOMOBILE ENGINEERING 2017年第11期231卷 1589-1602页

作者： An, Xiaodong Liu, Xinghua Sun, Baigang Beijing Inst Technol Sch Mech Engn Beijing 100081 Peoples R China

The nozzle opening pressure of fuel injection systems affects the initial fuel atomization, the fuel injection quantity, the emission characteristics and the operation stability of diesel engines. This paper presents an investigation on the dynamic characteristics of the nozzle opening pressure for a double-solenoid-valve fuel injection system. A numerical model for the nozzle opening pressure based on the fluid-structure interaction theory is established, including the models for the physical properties of the fuel, the leakage rate of the piston pair and the elastic deformation of the piston chamber and the piston pair. Also, experiments were carried out to validate the proposed model. Good agreement was found between the simulated results and the measured results. Based on this model, the effects of some factors on the nozzle opening pressure are analysed. The results show that the rotational speed of the cam, the initial clearance of the piston pair and the sealing length of the piston pair have slight effects on the nozzle opening pressure but that the diameter of the piston, the initial fuel temperature and the residual volume greatly influence the nozzle opening pressure.

关键词： Nozzle opening pressure double-solenoid-valve injection system fluid-structure interaction piston pair leakage rate elastic deformation

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A parallel monolithic approach for fluid-structure interaction in a cerebral aneurysm

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COMPUTERS & fluidS 2017年 153卷 61-75页

作者： Eken, Ali Sahin, Mehmet Istanbul Tech Univ Astronaut Engn Dept Fac Aeronaut & Astronaut TR-34469 Istanbul Turkey

A parallel fully-coupled numerical algorithm has been developed for the fluid-structure interaction problem in a cerebral artery with aneurysm. For the fluid part of the problem, an Arbitrary Lagrangian-Eulerian formulation based on the side-centered unstructured finite volume method is employed for the governing incompressible Navier-Stokes equations. The deformation of the solid domain is governed by the constitutive laws for the nonlinear Saint Venant-Kirchhoff material and the classical Galerkin finite element method is used to discretise the governing equations in a Lagrangian frame. The time integration method for the structure domain is based on the Newmark type generalized-alpha method while the second-order backward difference (BDF2) is used in the fluid domain. A special attention is given to construct an algorithm obeying the local/global discrete geometric conservation laws (DGCL) in order to conserve fluid volume at machine precision when the fluid domain is entirely enclosed by solid domain boundary. Therefore, a compatible kinematic boundary condition is applied at the interface between the solid and fluid domains. The parallel implementation of the present fully coupled unstructured fluid structure solver is based on the PETSc library and a one-level restricted additive Schwarz preconditioner with a block-incomplete factorization within each partitioned sub-domains is utilized for the resulting fully coupled system. The proposed algorithm is initially validated for a pressure pulse propagating in a flexible tube and the mass conservation accuracy is tested for a thin elastic sphere filled with an incompressible fluid in a circular tube. Then the numerical method is applied to a complicated problem involving unsteady pulsatile blood flow in a cerebral artery with aneurysm as a realistic fluid-structure interaction problem encountered in biomechanics. Various hemodynamic quantities of interest like fluid velocities, blood pressure and wall shear stress

关键词： fluid-structure interaction Cerebral aneurysm Monolithic method Unstructured finite volume method Finite element method

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Evaluation of an aortic valve prosthesis: fluid-structure interaction or structural simulation?

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JOURNAL OF BIOMECHANICS 2017年 58卷 45-51页

作者： Luraghi, Giulia Wu, Wei De Gaetano, Francesco Matas, Jose Felix Rodriguez Moggridge, Geoff D. Serrani, Marta Stasiak, Joanna Costantino, Maria Laura Migliavacca, Francesco Politecn Milan Dept Chem Mat & Chem Engn Giulio Natta Lab Biol Struct Mech LaBS Milan Italy Univ Cambridge Dept Chem Engn & Biotechnol Cambridge England

Bio-inspired polymeric heart valves (PHVs) are excellent candidates to mimic the structural and the fluid dynamic features of the native valve. PHVs can be implanted as prosthetic alternative to currently clinically used mechanical and biological valves or as potential candidate for a minimally invasive treatment, like the transcatheter aortic valve implantation. Nevertheless, PHVs are not currently used for clinical applications due to their lack of reliability. In order to investigate the main features of this new class of prostheses, pulsatile tests in an in-house pulse duplicator were carried out and reproduced in silico with both structural Finite-Element (FE) and fluid-structure interaction (FSI) analyses. Valve kinematics and geometric orifice area (GOA) were evaluated to compare the in vitro and the in silico tests. Numerical results showed better similarity with experiments for the FSI than for the FE simulations. The maximum difference between experimental and FSI GOA at maximum opening time was only 5%, as compared to the 46.5% between experimental and structural FE GOA. The stress distribution on the valve leaflets clearly reflected the difference in valve kinematics. Higher stress values were found in the FSI simulations with respect to those obtained in the FE simulation. This study demonstrates that FSI simulations are more appropriate than FE simulations to describe the actual behaviour of PHVs as they can replicate the valve-fluid interaction while providing realistic fluid dynamic results. (C) 2017 The Authors. Published by Elsevier Ltd.

关键词： fluid-structure interaction Polymeric heart valve Finite element analysis Cardiovascular mechanics

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The impact of the aortic valve impairment on the distant coronary arteries hemodynamics: a fluid-structure interaction study

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MEDICAL & BIOLOGICAL ENGINEERING & COMPUTING 2017年第10期55卷 1859-1872页

作者： Mohammadi, Hossein Cartier, Raymond Mongrain, Rosaire McGill Univ Dept Mech Engn Montreal PQ H3A 0C3 Canada Montreal Heart Inst Dept Cardiovasc Surg Montreal PQ H1T 1C8 Canada

Atherosclerosis is still the leading cause of death in the developed world. Although its initiation and progression is a complex multifactorial process, it is well known that blood flow-induced wall shear stress (WSS) is an important factor involved in early atherosclerotic plaque initiation. In recent clinical studies, it was established that the regional pathologies of the aortic valve can be involved in the formation of atherosclerotic plaques. However, the impact of hemodynamic effects is not yet fully elucidated for disease initiation and progression. In this study, our developed 3D global fluid-structure interaction model of the aortic root incorporating coronary arteries is used to investigate the possible interaction between coronary arteries and aortic valve pathologies. The coronary hemodynamics was examined and quantified for different degrees of aortic stenosis varying from nonexistent to severe. For the simulated healthy model, the calculated WSS varied between 0.41 and 1.34 Pa which is in the atheroprotective range. However, for moderate and severe aortic stenoses, wide regions of the coronary structures, especially the proximal sections around the first bifurcation, were exposed to lower values of WSS and therefore they were prone to atherosclerosis even in the case of healthy coronary arteries.

关键词： Coronary arteries hemodynamics Shear stress Aortic stenosis Coronary arteries pathologies fluid-structure interaction

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