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Using intravascular ultrasound image-based fluid-structure interaction models and machine learning methods to predict human coronary plaque vulnerability change

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COMPUTER METHODS IN BIOMECHANICS AND BIOMEDICAL ENGINEERING 2020年第15期23卷 1267-1276页

作者： Wang, Liang Tang, Dalin Maehara, Akiko Wu, Zheyang Yang, Chun Muccigrosso, David Matsumura, Mitsuaki Zheng, Jie Bach, Richard Billiar, Kristen L. Stone, Gregg W. Mintz, Gary S. Southeast Univ Sch Biol Sci & Med Engn Nanjing Peoples R China Worcester Polytech Inst Dept Math Sci Worcester MA 01609 USA Columbia Univ Cardiovasc Res Fdn New York NY USA Washington Univ Mallinckrodt Inst Radiol St Louis MO USA Washington Univ Sch Med Div Cardiovasc St Louis MO 63110 USA Worcester Polytech Inst Dept Biomed Engn Worcester MA 01609 USA

Plaque vulnerability prediction is of great importance in cardiovascular research. In vivo follow-up intravascular ultrasound (IVUS) coronary plaque data were acquired from nine patients to construct fluid-structure interaction models to obtain plaque biomechanical conditions. Morphological plaque vulnerability index (MPVI) was defined to measure plaque vulnerability. The generalized linear mixed regression model (GLMM), support vector machine (SVM) and random forest (RF) were introduced to predict MPVI change (Delta MPVI = MPVIfollow-up-MPVIbaseline) using ten risk factors at baseline. The combination of mean wall thickness, lumen area, plaque area, critical plaque wall stress, and MPVI was the best predictor using RF with the highest prediction accuracy 91.47%, compared to 90.78% from SVM, and 85.56% from GLMM. Machine learning method (RF) improved the prediction accuracy by 5.91% over that from GLMM. MPVI was the best single risk factor using both GLMM (82.09%) and RF (78.53%) while plaque area was the best using SVM (81.29%).

关键词： Coronary artery disease fluid-structure interaction machine learning plaque vulnerability prediction intravascular ultrasound

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A multi-vector interface quasi-Newton method with linear complexity for partitioned fluid-structure interaction

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COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING 2020年 361卷 112810-000页

作者： Spenke, Thomas Hosters, Norbert Behr, Marek Rhein Westfal TH Aachen CCES Chair Computat Anal Tech Syst CATS D-52062 Aachen Germany

In recent years, interface quasi-Newton methods have gained growing attention in the fluid-structure interaction community by significantly improving partitioned solution schemes: They not only help to control the inherent added-mass instability, but also prove to substantially speed up the coupling's convergence. In this work, we present a novel variant: The key idea is to build on the multi-vector Jacobian update scheme first presented by Bogaers et al. (2014) and avoid any explicit representation of the (inverse) Jacobian approximation, since it slows down the solution for large systems. Instead, all terms involving a quadratic complexity have been systematically eliminated. The result is a new multi-vector interface quasi-Newton variant whose computational cost scales linearly with the problem size. (C) 2020 Elsevier B.V. All rights reserved.

关键词： fluid-structure interaction Interface quasi-Newton methods Partitioned algorithm

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Topology optimization of binary structures under design-dependent fluid-structure interaction loads

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STRUCTURAL AND MULTIDISCIPLINARY OPTIMIZATION 2020年第4期62卷 2101-2116页

作者： Picelli, R. Ranjbarzadeh, S. Sivapuram, R. Gioria, R. S. Silva, E. C. N. Univ Sao Paulo Dept Min & Petr Engn Praca Narciso Andrade S-N BR-11013560 Santos SP Brazil Univ Sao Paulo Dept Mechatron & Mech Syst Engn Av Prof Mello Moraes 2231 BR-05508030 Sao Paulo SP Brazil Univ Calif San Diego Dept Struct Engn 9500 Gilman Dr La Jolla CA 92093 USA

A current challenge for the structural topology optimization methods is the development of trustful techniques to account for different physics interactions. This paper devises a technique that considers separate physics analysis and optimization within the context of fluid-structure interaction (FSI) systems. Steady-state laminar flow and small structural displacements are assumed. We solve the compliance minimization problem subject to single or multiple volume constraints considering design-dependent FSI loads. For that, the TOBS (topology optimization of binary structures) method is applied. The TOBS approach uses binary {0,1} design variables, which can be advantageous when dealing with design-dependent physics interactions, e.g., in cases where fluid-structure boundaries are allowed to change during optimization. The COMSOL Multiphysics software is used to solve the fluid-structure equations and output the sensitivities using automatic differentiation. The TOBS optimizer provides a new set of {0,1} variables at every iteration. Numerical examples show smoothly converged solutions.

关键词： Topology optimization fluid-structure interaction Laminar flow Small displacements Binary variables Design-dependent loads COMSOL multiphysics

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Analysis of temperature-sensitive hydrogel microvalves in a T-junction flow sorter using full scale fluid-structure interaction

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JOURNAL OF INTELLIGENT MATERIAL SYSTEMS AND structureS 2020年第11期31卷 1371-1382页

作者： Khanjani, Elham Kargar-Estahbanaty, Arash Taheri, Ali Baghani, Mostafa Univ Tehran Coll Engn Sch Mech Engn Tehran Iran Univ Calif Riverside Marlan & Rosemary Bourns Coll Engn Riverside CA 92521 USA Univ Larestan Mech Engn Dept Azadi Blvd Lar *** Iran

Hydrogels have attracted attention in microfluidic applications as sensors and actuators due to their ability to undergo huge volume changes when subjected to environmental stimuli. In this study, a T-junction flow sorter is numerically investigated. Each of the branches involves one hydrogel microvalve with reverse sensitivity to temperature changes. The valve's functionality is studied with and without considering fluid-structure interaction for various inlet pressures. The results of fluid-structure interaction and non-fluid-structure interaction solutions, such as fluid flow rate and valves close temperature, are presented and compared. In order to reduce hydrogel's response time, the solution is employed for multiple valves patterns. It can be concluded that the hydrogel deformation due to the fluid pressure has a significant effect on the valves' operational parameters which cannot be ignored in design and analysis.

关键词： temperature-sensitive hydrogel flow sorter microvalve fluid-structure interaction finite element method

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A mass-spring fluid-structure interaction solver: Application to flexible revolving wings

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COMPUTERS & fluidS 2020年第0期200卷 104426-000页

作者： Hung Truong Engels, Thomas Kolomenskiy, Dmitry Schneider, Kai Aix Marseille Univ Cent Marseille CNRS I2M UMR 7373 39 Rue Joliot Curie F-13451 Marseille 20 France Ecole Normale Super PSL LMD IPSL 24 Rue Lhomond F-75231 Paris 05 France Japan Agcy Marine Earth Sci & Technol JAMSTEC Kanazawa Ku 3173-25 Showa Machi Yokohama Kanagawa 2360001 Japan

The secret to the spectacular flight capabilities of flapping insects lies in their wings, which are often approximated as flat, rigid plates. Real wings are however delicate structures, composed of veins and membranes, and can undergo significant deformation. In the present work, we present detailed numerical simulations of such deformable wings. Our results are obtained with a fluid-structure interaction solver, coupling a mass-spring model for the flexible wing with a pseudo-spectral code solving the incompressible Navier-Stokes equations. We impose the no-slip boundary condition through the volume penalization method;the time-dependent complex geometry is then completely described by a mask function. This allows solving the governing equations of the fluid on a regular Cartesian grid. Our implementation for massively parallel computers allows us to perform high resolution computations with up to 500 million grid points. The mass-spring model uses a functional approach, thus modeling the different mechanical behaviors of the veins and the membranes of the wing. We perform a series of numerical simulations of a flexible revolving bumblebee wing at a Reynolds number Re = 1800. In order to assess the influence of wing flexibility on the aerodynamics, we vary the elasticity parameters and study rigid, flexible and highly flexible wing models. Code validation is carried out by computing classical benchmarks. (C) 2020 Elsevier Ltd. All rights reserved.

关键词： Insect flight Wing elasticity Mass-spring model fluid-structure interaction Spectral method Volume penalization method

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interaction of a deformable solid with two-phase flows: An Eulerian-based numerical model for fluid-structure interaction using the level contour reconstruction method

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INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN fluidS 2020年第11期92卷 1478-1505页

作者： Shin, Seungwon Chergui, Jalel Juric, Damir Hongik Univ Dept Mech & Syst Design Engn Sangsu Dong 72-1 Seoul 121791 South Korea Univ Paris Saclay CNRS LIMSI Orsay France

We describe the formulation of a method for fluid-structure interaction involving the coupling of moving and/or flexible solid structures with multiphase flows in the framework of the Level Contour Reconstruction Method. We present an Eulerian-based numerical procedure for tracking the motion and interaction of a liquid-gas interface with a fluid-solid interface in the Lagrangian frame together with the evaluation of the fluid transport equations coupled to those for the solid transport, namely the left Cauchy-Green strain tensor field, in the Eulerian frame. To prevent excessive dissipation due to the convective nature of the solid transport equation, a simple incompressibility constraint for the strain field is enforced. A single grid structure is used for both the fluid and solid phases which allows for a simple and natural coupling of the fluid and solid dynamics. Several benchmark tests are performed to show the accuracy of the numerical method and which demonstrate accurate results compared to several of those in the existing literature. In particular we show that surface tension effects including contact line dynamics on the deforming solid phase can be properly simulated. The three-phase interaction of a droplet impacting on a flexible cantilever is investigated in detail. The simulations follow the detailed motion of the droplet impact (and subsequent deformation, breakup, and fall trajectory) along with the motion of the deformable solid cantilever due to its own weight as well as due to the force of the droplet impact.

关键词： Eulerian-based formulation fluid-structure interaction front-tracking method multiphase flow numerical simulation solid stress

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A Reduced-Order Flow Model for fluid-structure interaction Simulation of Vocal Fold Vibration

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JOURNAL OF BIOMECHANICAL ENGINEERING-TRANSACTIONS OF THE ASME 2020年第2期142卷 6-6页

作者： Li, Zheng Chen, Ye Chang, Siyuan Luo, Haoxiang Vanderbilt Univ Dept Mech Engn 2301 Vanderbilt Pl Nashville TN 37235 USA

We present a novel reduced-order glottal airflow model that can be coupled with the three-dimensional (3D) solid mechanics model of the vocal fold tissue to simulate the fluid-structure interaction (FSI) during voice production. This type of hybrid FSI models have potential applications in the estimation of the tissue properties that are unknown due to patient variations and/or neuromuscular activities. In this work, the flow is simplified to a one-dimensional (1D) momentum equation-based model incorporating the entrance effect and energy loss in the glottis. The performance of the flow model is assessed using a simplified yet 3D vocal fold configuration. We use the immersed-boundary method-based 3D FSI simulation as a benchmark to evaluate the momentum-based model as well as the Bernoulli-based 1D flow models. The results show that the new model has significantly better performance than the Bernoulli models in terms of prediction about the vocal fold vibration frequency, amplitude, and phase delay. Furthermore, the comparison results are consistent for different medial thicknesses of the vocal fold, subglottal pressures, and tissue material behaviors, indicating that the new model has better robustness than previous reduced-order models.

关键词： vocal fold fluid-structure interaction reduced-order model phonation

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Accurate iteration-free mixed-stabilised formulation for laminar incompressible Navier-Stokes: Applications to fluid-structure interaction

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JOURNAL OF fluidS AND structureS 2020年 97卷 103077-103077页

作者： Kadapa, Chennakesava Dettmer, Wulf G. Peric, Djordje Swansea Univ Swansea Acad Adv Comp Swansea SA1 8EN W Glam Wales Swansea Univ Zienkiewicz Ctr Computat Engn ZCCE Swansea SA1 8EN W Glam Wales

Stabilised mixed velocity-pressure formulations are one of the widely-used finite element schemes for computing the numerical solutions of laminar incompressible Navier-Stokes. In these formulations, the Newton-Raphson scheme is employed to solve the nonlinearity in the convection term. One fundamental issue with this approach is the computational cost incurred in the Newton-Raphson iterations at every load/time step. In this paper, we present an iteration-free mixed finite element formulation for incompressible Navier-Stokes that preserves second-order temporal accuracy of the generalised-alpha and related schemes for both velocity and pressure fields. First, we demonstrate the second-order temporal accuracy using numerical convergence studies for an example with a manufactured solution. Later, we assess the accuracy and the computational benefits of the proposed scheme by studying the benchmark example of flow past a fixed circular cylinder. Towards showcasing the applicability of the proposed technique in a wider context, the inf-sup stable P2-P1 pair for the formulation without stabilisation is also considered. Finally, the resulting benefits of using the proposed scheme for fluid-structure interaction problems are illustrated using two benchmark examples in fluid-flexible structure interaction. (C) 2020 Elsevier Ltd. All rights reserved.

关键词： Incompressible Navier-Stokes SUPG/PSPG stabilisation Newton-Raphson scheme fluid-structure interaction

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Computational hemodynamics in arteries with the one-dimensional augmented fluid-structure interaction system: viscoelastic parameters estimation and comparison with in-vivo data

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JOURNAL OF BIOMECHANICS 2020年第0期100卷 109595-000页

作者： Bertaglia, Giulia Navas-Montilla, Adrian Valiani, Alessandro Monge Garcia, Manuel Ignacio Murillo, Javier Caleffi, Valerio Univ Ferrara Dept Engn Via G Saragat 1 I-44122 Ferrara Italy Univ Zaragoza Fluid Mech LIFTEC CSIC Calle Maria de Luna 3 Zaragoza 50018 Spain Hosp SAS Jerez Intens Care Unit Jerez de la Frontera 11407 Spain

Mathematical models are widely recognized as a valuable tool for cardiovascular diagnosis and the study of circulatory diseases, especially to obtain data that require otherwise invasive measurements. To correctly simulate body hemodynamics, the viscoelastic properties of vessels walls are a key aspect to be taken into account as they play an essential role in cardiovascular behavior. The present work aims to apply the augmented fluid-structure interaction system of blood flow to real case studies to assess the validity of the model as a valuable resource to improve cardiovascular diagnostics and the treatment of pathologies. Main contributions of the paper include the evaluation of viscoelastic tube laws, estimation of viscoelastic parameters and comparison of models with literature results and in-vivo experiments. The ability of the model to correctly simulate pulse waveforms in single arterial segments is verified using literature benchmark test cases, designed taking into account a simple elastic behavior of the wall in the upper thoracic aorta and in the common carotid artery. Furthermore, in-vivo pressure waveforms, extracted from tonometric measurements performed on four human common carotid arteries and two common femoral arteries, are compared to numerical solutions. It is highlighted that the viscoelastic damping effect of arterial walls is required to avoid an overestimation of pressure peaks. Finally, an effective procedure to estimate the viscoelastic parameters of the model is herein proposed, which returns hysteresis curves of the common carotid arteries dissipating energy fractions in line with values calculated from literature hysteresis loops in the same vessel. (C) 2019 Elsevier Ltd. All rights reserved.

关键词： Blood flow One-dimensional models Arterial hemodynamics Viscoelastic effects fluid-structure interaction

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Three-dimensional fluid-structure interaction simulations of a yarn subjected to the main nozzle flow of an air-jet weaving loom using a Chimera technique

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TEXTILE RESEARCH JOURNAL 2020年第2期90卷 194-212页

作者： Delcour, Lucas Peeters, Jozef Degroote, Joris Univ Ghent Dept Flow Heat & Combust Mech Fac Engn & Architecture Ghent Belgium Picanol NV Ieper Belgium Flanders Make Lommel Belgium

In air-jet weaving looms, the main nozzle pulls the yarn from the prewinder by means of a high velocity air flow. The flexible yarn is excited by the flow and exhibits high amplitude oscillations. The motion of the yarn is important for the reliability and the attainable speed of the insertion. fluid-structure interaction simulations calculate the interaction between the air flow and the yarn motion and could provide additional insight into yarn behavior. However, the use of an arbitrary Lagrangian-Eulerian approach for the deforming fluid domain around a flexible yarn typically results in severe mesh degradation, vastly reducing the accuracy of the calculations or limiting the physical time that can be simulated. In this research, the feasibility of using a Chimera technique to simulate the motion of a yarn interacting with the air flow from a main nozzle was investigated. This methodology combines a fixed background grid with a moving component grid deforming along with the yarn. The component grid is, however, not constrained by the boundaries of the flow domain allowing for large deformations with limited mesh degradation. Two separate cases were investigated. In the first case, the yarn was considered to be clamped at the main nozzle inlet. For the second case, the yarn was allowed to move axially as the main nozzle pulled it from a drum storage system.

关键词： weft yarn insertion main nozzle fluid-structure interaction dynamic mesh Chimera overset

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