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作者： Hoekstra, Joshua McMaster University

学位级别：硕士

The long-term operational safety of nuclear power plants is of utmost importance. Seismic isolation has been shown to be effective in reducing the demands on structures in many applications, including nuclear power plants (NPP). Many designs for Generation III+ NPP include a large passive cooling tank as a measure of safety that can be used during power failure. In a large seismic event, the fluid in the tank may be excited, and while the phenomenon of fluid-structure interaction (FSI) has also been studied in the context of base isolated liquid storage tanks, the effect on seismically isolated NPP has not yet been explored. This thesis presents a two-part study on a base isolated NPP with friction pendulum bearings. The first part of the study compares the usage of a linear fluid model to a nonlinear fluid model in determining tank and structural demand parameters. The linear fluid model was found to represent the nonlinear fluid model well for preliminary analysis apart from peak sloshing height, which it consistently underestimated. The second part of the study uses a linear fluid model, an empty tank model and a rigid fluid model to investigate the influence of FSI on the structural response of an isolated NPP compared to a fixed base NPP. In general, the response of a fixed base NPP considering FSI using a linear fluid model can typically be bound by the results assuming an empty tank and assuming a full tank with rigid fluid mass. However, this does not hold for the base isolated NPP, as the peak isolation displacement for an NPP with a linear fluid model at design depth is greater than the peak isolation displacement than the same NPP with an empty tank and with a rigid fluid model. Thesis Master of Applied Science (MASc)

关键词： fluid-structure interaction Nuclear Power Plant Base Isolation

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An immersed edge-based smoothed finite element method with the stabilized pressure gradient projection for fluid-structure interaction

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COMPUTERS & structureS 2022年 270卷

作者： Wang, G. Hong, Y. Huo, S. H. Jiang, C. Hebei Univ Technol State Key Lab Reliabil & Intelligence Elect Equipm Tianjin 300130 Peoples R China Hebei Univ Technol Sch Mech Engn Tianjin 300401 Peoples R China Taiyuan Univ Technol Coll Aeronaut & Astronaut Taiyuan 030024 Peoples R China Cent South Univ Sch Traff & Transportat Engn Key Lab Traff Safety Track Minist Educ Changsha 410076 Peoples R China

In this paper, an effective and stable immersed edge-based smoothed finite element method (IES-FEM) is presented for fluid-structure interaction (FSI) problems. Under the framework of immersed algorithm, the system equation can be decomposed into three components, i.e, equations of nonlinear structure, incompressible viscous fluid, and FSI force. The characteristic-based split (CBS) scheme is first used to alleviate the spatial oscillation in the Navier-Stokes (N-S) equation. After that, the second-order pressure accuracy is formulated in the original CBS via stabilized pressure gradient projection (SPGP). Then, the problem domains are discretized using the simplest three-node triangular element and the smoothing domains are established. In order to enhance the accuracy of lower-order interpolation, the edge based smoothing operation is further performed on all gradient-related terms for structure and fluid, namely, the coupled ES/ES-FEM. Moreover, an accurate form of FSI force evaluation is developed by introducing the whole function that considers the pressure and viscous force on the interface. Numerical examples demonstrate that the proposed scheme has higher computational precision (even for distorted mesh), faster convergence rate, good robustness, and lower computed costs.(c) 2022 Elsevier Ltd. All rights reserved.

关键词： Numerical methods Characteristic-based split scheme Stabilized by pressure gradient projection Edge-based smoothed finite element method Gradient smoothing technique fluid-structure interaction

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An isogeometric b-rep mortar-based mapping method for non-matching grids in fluid-structure interaction

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ADVANCED MODELING AND SIMULATION IN ENGINEERING SCIENCES 2021年第1期8卷 1-55页

作者： Apostolatos, Andreas Emiroglu, Altug Shayegan, Shahrokh Pean, Fabien Bletzinger, Kai-Uwe Wuechner, Roland Tech Univ Munich Chair Struct Anal Arcisstr 21 D-80333 Munich Germany Swiss Fed Inst Technol Zurich Comp Vis Lab Sternwartstr 7 CH-8092 Zurich Switzerland

In this study the isogeometric B-Rep mortar-based mapping method for geometry models stemming directly from Computer-Aided Design (CAD) is systematically augmented and applied to partitioned fluid-structure interaction (FSI) simulations. Thus, the newly proposed methodology is applied to geometries described by their Boundary Representation (B-Rep) in terms of trimmed multipatch Non-Uniform Rational B-Spline (NURBS) discretizations as standard in modern CAD. The proposed isogeometric B-Rep mortar-based mapping method is herein extended for the transformation of fields between a B-Rep model and a low order discrete surface representation of the geometry which typically results when the Finite Volume Method (FVM) or the Finite Element Method (FEM) are employed. This enables the transformation of such fields as tractions and displacements along the FSI interface when Isogeometric B-Rep Analysis (IBRA) is used for the structural discretization and the FVM is used for the fluid discretization. The latter allows for diverse discretization schemes between the structural and the fluid Boundary Value Problem (BVP), taking into consideration the special properties of each BVP separately while the constraints along the FSI interface are satisfied in an iterative manner within partitioned FSI. The proposed methodology can be exploited in FSI problems with an IBRA structural discretization or to FSI problems with a standard FEM structural discretization in the frame of the Exact Coupling Layer (ECL) where the interface fields are smoothed using the underlying B-Rep parametrization, thus taking advantage of the smoothness that the NURBS basis functions offer. All new developments are systematically investigated and demonstrated by FSI problems with lightweight structures whereby the underlying geometric parametrizations are directly taken from real-world CAD models, thus extending IBRA into coupled problems of the FSI type.

关键词： Mortar-based mapping Isogeometric B-Rep analysis Trimmed NURBS multipatches Exact coupling layer Penalty method fluid-structure interaction

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An immersed finite element material point (IFEMP) method for free surface fluid-structure interaction problems

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COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING 2022年 393卷

作者： Li, Ming-Jian Lian, Yanping Zhang, Xiong Beijing Inst Technol Inst Adv Struct Technol Beijing 100081 Peoples R China Tsinghua Univ Sch Aerosp Engn Beijing 100084 Peoples R China

The inherent nonlinearity of free surface fluid-structure interaction (FSI) problems challenges numerical methods in terms of efficiency and fidelity. In this article, we propose an immersed finite element material point method for the water entry fluid-structure interaction problems. In this method, the fluid domain is discretized by an improved incompressible material point method (iMPM) using both Eulerian and Lagrangian descriptions, while the solid domain is solved by finite element method (FEM). The interaction between the iMPM and FEM is handled by a sharp immersed interface approach. Moreover, weighted tracing points are designed to track the fluid-structure interface with a low time complexity;a particle rearranging method is developed to eliminate the numerical cavities, which are non-physical voids caused by the highly disordered particle distribution, from which the original iMPM for FSI problems suffers. Various free surface FSI problems are presented to demonstrate the accuracy and effectiveness of the proposed method. The computational results are compared with analytical, experimental, and simulation data from the literature, with good agreement in cases where such data is available. The proposed method is expected to be a powerful tool for free surface FSI problems. (C) 2022 Elsevier B.V. All rights reserved.

关键词： fluid-structure interaction Multiphase flow Immersed boundary Water entry Material point method

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Numerical methodology based on fluid-structure interaction to predict the residual stress distribution in glass tempering considering non-uniform cooling

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COMPUTERS & structureS 2022年 264卷

作者： Iglesias, A. Martinez-Agirre, M. Torca, I Llavori, I Esnaola, J. A. Mondragon Unibertsitatea Engn Fac Struct Mech & Design Arrasate Mondragon Spain Mondragon Unibertsitatea Engn Fac Fluid Mech Arrasate Mondragon Spain

In this paper a novel numerical methodology for calculating non-uniform residual stress distributions during the glass tempering process is presented. Tempering techniques lead to non-uniform heat transfer rates causing residual stress inhomogeneities, which consequently have a direct impact on the structural behaviour of components. Nevertheless, most works in the literature do not consider the influence of local flow phenomena during thermal calculations, resulting in non-representative residual stress distributions. In this context, a novel generalised methodology based on a fluid-structure interaction one-way approach to sequentially couple the thermal and mechanical fields is presented. In this way, the unsteady and non-uniform heat transfer rate is coupled with the Narayanaswamy model to predict the non-homogeneous residual stress pattern. The obtained numerical results for the analysed impinging jet array case are in good agreement both quantitatively and qualitatively, exhibiting an average error below 10% with respect to previous experimental investigations. Finally, efforts are made to reduce the computational time. Therefore, the proposed methodology proves to be an efficient tool for understanding the underlying mechanisms and predicting the residual stress distributions during glass tempering. (C) 2022 Elsevier Ltd. All rights reserved.

关键词： fluid-structure interaction Glass tempering Residual stresses Inhomogeneities Volumetric radiation

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A reduced unified continuum formulation for vascular fluid-structure interaction

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COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING 2022年 394卷

作者： Lan, Ingrid S. Liu, Ju Yang, Weiguang Marsden, Alison L. Stanford Univ Dept Bioengn Stanford CA 94305 USA Southern Univ Sci & Technol Dept Mech & Aerosp Engn Shenzhen 518055 Guangdong Peoples R China Southern Univ Sci & Technol Guangdong Hong Kong Macao Joint Lab Data Driven F Shenzhen 518055 Guangdong Peoples R China Stanford Univ Dept Pediat Cardiol Stanford CA 94305 USA Stanford Univ Inst Computat & Math Engn Stanford CA 94305 USA

We recently derived the unified continuum and variational multiscale formulation for fluid-structure interaction (FSI) using the Gibbs free energy as the thermodynamic potential. Restricting our attention to vascular FSI, we now reduce this formulation in arbitrary Lagrangian-Eulerian (ALE) coordinates by adopting three common modeling assumptions for the vascular wall. The resulting semi-discrete formulation, referred to as the reduced unified continuum formulation, achieves monolithic coupling of the FSI system in the Eulerian frame through a simple modification of the fluid boundary integral. While ostensibly similar to the semi-discrete formulation of the coupled momentum method introduced by Figueroa et al., its underlying derivation does not rely on an assumption of a fictitious body force in the elastodynamics sub-problem and therefore represents a direct simplification of the ALE method. Furthermore, uniform temporal discretization of the entire FSI system is performed via the generalized-alpha scheme. In contrast to the predominant approach yielding only first-order accuracy for pressure, we collocate both pressure and velocity at the intermediate time step to achieve uniform second-order temporal accuracy. In conjunction with quadratic tetrahedral elements, our methodology offers higher-order temporal and spatial accuracy for quantities of clinical interest, including pressure and wall shear stress. Furthermore, without loss of consistency, a segregated predictor multi-corrector algorithm is developed to preserve the same block structure as for the incompressible Navier-Stokes equations in the implicit solver's associated linear system. Block preconditioning of a monolithically coupled FSI system is therefore made possible for the first time. Compared to alternative preconditioners, our three-level nested block preconditioner, which achieves improved representation of the Schur complement, demonstrates robust performance over a wide range of physical param

关键词： fluid-structure interaction Unified continuum formulation Variational multiscale method Nested block preconditioner Womersley solution Patient-specific hemodynamics

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A peridynamics-immersed boundary-lattice Boltzmann method for fluid-structure interaction analysis

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OCEAN ENGINEERING 2022年 264卷

作者： Yang, Fei Gu, Xin Xia, Xiaozhou Zhang, Qing Hohai Univ Coll Mech & Mat Dept Engn Mech Nanjing 211100 Peoples R China

ABS T R A C T fluid-structure interaction problems (FSI) are ubiquitous in nature and industrial production. Numerical simu-lation has been taken as an effective method for fluid-structure interaction analysis. To accurately and efficiently simulate the deformation and fracture of structure induced by fluid-structure interactions, a novel PD-IB-LBM is proposed. Specifically, the structural deformation and fracture is described by the improved bond-based peri-dynamic (PD) model with an attenuation kernel function and surface effect correction, and the fluid flow is modeled by the lattice Boltzmann method (LBM), together with immersed boundary method (IBM) as a solid bridge to realize the bi-directional coupling at the fluid-solid interface. Therefore, the generation of body conformal mesh and mesh reconstruction are avoided, and the damage and fracture of structure and the movement of the fluid can be well described. In addition, the velocity correction of fluid and solid is achieved by solving a linear system of equations derived from IBM, which eliminates the trouble of iterative solution between fluid and solid for the traditional coupling method. The proposed model is validated through the simulation of flow past a circular cylinder, a rotating ring in a square fluid, and the fracture of the beam in a fluid tunnel. The simulation results show that the proposed PD-IB-LBM model and algorithm can effectively predict the discon-tinuous mechanical behaviors such as damage and crack propagation of structure under complex fluid motion.

关键词： fluid-structure interaction Peridynamics Lattice Boltzmann method Immersed boundary method

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Study on the Effect of Fracturing Pump Start and Stop on Tubing fluid-structure interaction Vibration in HPHT Wells via MOC

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ENERGIES 2022年第24期15卷

作者： Cui, Lu Qiao, Fanfan Li, Meng Xiao, Yiming Cheng, Jiarui Xian Shiyou Univ Xian Key Lab Wellbore Integr Evaluat Xian Peoples R China

The processes of HTHP well fracturing, oil drive, and gas recovery are accompanied by the non-stationary flow of medium in the tubing, which may lead to periodic vibration and cause the failure and fatigue of the tubing, thread leakage, and bending deformation. In this paper, a fluid-structure interaction model with 4-equation was established, which considered the unsteady flow of fluid and the motion state of tubing during the periodic injection, pump start, and shutdown of fluid in the tubing. Further, the discrete solution of MOC was used to obtain the variation of fluid flow rate and pressure, tubing vibration rate, frequency, and additional stress with time. The resonance construction parameters corresponding to different tubing diameters were analyzed by discussing the effects of different start and shutdown times as well as pressure on the tubing vibration parameters. The results show that under the periodic injection condition, increasing the tubing diameter or start inside pressure would lead to a sharp increase in the axial additional stress of the tubing generated by fluid-structure interaction, which is not conducive to the safety protection of the tubing. When the pump was shutdown, excessively short operation times and high pressure in the tubing would lead to excessive transient loads in addition to resonance, which would cause damage to the pipeline. Finally, corresponding to the above analysis results, this paper proposes the optimal injection parameters to avoid the generation of resonance, which provides a theoretical basis and reference range for the safe service conditions of the tubing.

关键词： tubing fluid-structure interaction method of characteristics (MOC) pump start and shutdown conditions resonance

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Modeling fluid-structure interaction with the edge-based smoothed finite element method

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JOURNAL OF COMPUTATIONAL PHYSICS 2022年 460卷

作者： He, Tao Shanghai Normal Univ Dept Civil Engn Shanghai 201418 Peoples R China

We address in this work the numerical modeling of fluid-structure interaction (FSI) with the edge-based smoothed finite element method (ESFEM). We prove that the smoothed Galerkin weak-form integral of the Navier-Stokes equations is very flexible in the ESFEM. A simple integration scheme is accordingly proposed to facilitate the weak form approximation. The ESFEM is subsequently used for the elastodynamics equation and interface conditions as a matter of course. The FSI system is completely formulated in the edge-based notion and then is iteratively solved in a partitioned way. Numerical results obtained with the ESFEM are convincing in various FSI examples, indicating that the method can be a general solution approach to not only FSI but also many other real world phenomena. (c) 2022 Elsevier Inc. All rights reserved.

关键词： Edge-based smoothed finite element method Gradient smoothing Smoothed weak-form integral Integration point Navier-Stokes fluid-structure interaction

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A fluid-structure interaction model accounting arterial vessels as a key part of the blood-flow engine for the analysis of cardiovascular diseases

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FRONTIERS IN BIOENGINEERING AND BIOTECHNOLOGY 2022年 10卷 981187页

作者： Cheng, Heming Li, Gen Dai, Jifeng Zhang, Ke Xu, Tianrui Wei, Liuchuang Zhang, Xue Ding, Dongfang Hou, Jie Li, Jianyun Zhuang, Jiangping Tan, Kaijun Guo, Ran Kunming Univ Sci & Technol Dept Mech Kunming Peoples R China Kunming Univ Sci & Technol Fac Civil Engn & Mech Kunming Peoples R China Kunming Univ Sci & Technol Dept Hydraul Engn Kunming Peoples R China Kunming Univ Sci & Technol Fac Life Sci & Technol Kunming Peoples R China

According to the classical Windkessel model, the heart is the only power source for blood flow, while the arterial system is assumed to be an elastic chamber that acts as a channel and buffer for blood circulation. In this paper we show that in addition to the power provided by the heart for blood circulation, strain energy stored in deformed arterial vessels in vivo can be transformed into mechanical work to propel blood flow. A quantitative relationship between the strain energy increment and functional (systolic, diastolic, mean and pulse blood pressure) and structural (stiffness, diameter and wall thickness) parameters of the aorta is described. In addition, details of blood flow across the aorta remain unclear due to changes in functional and other physiological parameters. Based on the arterial strain energy and fluid-structure interaction theory, the relationship between physiological parameters and blood supply to organs was studied, and a corresponding mathematical model was developed. The findings provided a new understanding about blood-flow circulation, that is, cardiac output allows blood to enter the aorta at an initial rate, and then strain energy stored in the elastic arteries pushes blood toward distal organs and tissues. Organ blood supply is a key factor in cardio-cerebrovascular diseases (CCVD), which are caused by changes in blood supply in combination with multiple physiological parameters. Also, some physiological parameters are affected by changes in blood supply, and vice versa. The model can explain the pathophysiological mechanisms of chronic diseases such as CCVD and hypertension among others, and the results are in good agreement with epidemiological studies of CCVD.

关键词： cardio-cerebrovascular diseases strain energy arterial vessels physiological parameters blood supply fluid-structure interaction

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