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fluid-structure interaction in axially symmetric models of abdominal aortic aneurysms

PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART H-JOURNAL OF ENGINEERING IN MEDICINE 2009年第H2期223卷 195-209页

作者： Fraser, K. H. Li, M-X Lee, W. T. Easson, W. J. Hoskins, P. R. Univ Edinburgh Dept Med Phys Edinburgh EH16 4SB Midlothian Scotland Univ Edinburgh Sch Engn & Elect Edinburgh EH16 4SB Midlothian Scotland

Abdominal aortic aneurysm disease progression is probably influenced by tissue stresses and blood flow conditions and so accurate estimation of these will increase understanding of the disease and may lead to improved clinical practice. In this work the blood flow and tissue stresses in axially symmetric aneurysms are calculated using a complete fluid-structure interaction as a benchmark for calculating the error introduced by simpler calculations: rigid walled for the blood flow, homogeneous pressure for the tissue stress, as well as one-way-coupled interactions. The error in the peak von Mises stress in a homogeneous pressure calculation compared with a fluid-structure interaction calculation was less than 3.5 per cent for aneurysm diameters up to 7 cm. The error in the mean wall shear stress, in a rigid-walled calculation compared with a fluid-structure interaction calculation, varied from 30 per cent to 60 per cent with increasing aneurysm diameter. These results suggest that incorporation of the fluid-structure interaction is unnecessary for purely mechanical modelling, with the aim of evaluating the current rupture probability. However, for more complex biological modelling, perhaps with the aim of predicting the progress of the disease, where accurate estimation of the wall shear stress is essential, some form of fluid-structure interaction is necessary.

关键词： fluid-structure interaction abdominal aortic aneurysm haemodynamics wall shear stress rupture finite element analysis computational fluid dynamics blood flow artery

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fluid-structure interaction analysis of a hypothetical core disruptive accident in LMFBRs

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NUCLEAR ENGINEERING AND DESIGN 2005年第6期235卷 701-712页

作者： Liu, C Zhang, X Lu, MW Tsinghua Univ Dept Engn Mech Beijing 100084 Peoples R China

To ensure safety, it is necessary to assess the integrity of a reactor vessel of liquid-metal fast breeder reactor (LMFBR) under HCDA. Several important problems for a fluid-structural interaction analysis of HCDA are discussed in the present paper. Various loading models of hypothetical core disruptive accident (HCDA) are compared and the polytropic processes of idea gas (PPIG) law is recommended. In order to define a limited total energy release, a "5 % truncation criterion" is suggested. The relationship of initial pressure of gas bubble and the total energy release is given. To track the moving interfaces and to avoid the severe mesh distortion an arbitrary Lagrangrian-Eulerian (ALE) approach is adopted in the finite element modeling (FEM) analysis. Liquid separation and splash from a free surface are discussed. By using an elasticity solution under locally uniform pressure, two simplified analytical solutions for 3D and axi-symmetric case of the liquid impact pressure on roof slab are derived. An axi-symmetric finite elements code FRHCDA for fluid-structure interaction analysis of hypothetical core disruptive accident in LMFBR is developed. The CONT benchmark problem is calculated. The numerical results agree well with those from published papers. (C) 2004 Elsevier B.V. All rights reserved.

关键词： fluid-structure interaction FINITE element method STRENGTH of materials fluid dynamics

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fluid-structure interaction, immersed boundary-finite element method simulations of bio-prosthetic heart valves

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COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING 2013年第Apr.15期257卷 103-116页

作者： Borazjani, Iman SUNY Buffalo Dept Mech & Aerosp Engn Buffalo NY 14260 USA

A three-dimensional fluid-structure interaction (FSI) framework for rigid bodies has been extended to deformable soft tissue by coupling a sharp-interface immersed boundary incompressible Navier-Stokes solver for fluids with a non-linear large deformation finite element method for soft tissue. A Fung-type constitutive law is used for the soft tissue of heart valves that can capture the experimentally observed non-linear anisotropic stress-strain behavior of the heart valve tissue. The FSI solver adopts a strongly-coupled partitioned approach that is stabilized with under-relaxation and the Aitken acceleration technique. The finite element solver is verified against the benchmark experimental and numerical data for heart valve tissue while the immersed boundary solver was validated against flow measurements of a mechanical heart valve in the previous work. The capabilities of the solver are demonstrated by simulating the first fully three-dimensional fluid-structure interaction of tissue valves implanted in the aortic position during systole under physiologic flow conditions. It is observed that the flow's threefold symmetry breaks during the early systole, questioning the threefold symmetry assumption of previous simulations. The flow created by the tissue valve is compared against the mechanical heart valve under the same conditions. The flowfields, created by the tissue and mechanical valves, show drastic differences at different instances during a heartbeat cycle. Mainly, the breakdown of vortices into small-scale vortical structures right before the peak systole in mechanical heart valves is not observed in the bio-prosthetic heart valves. (C) 2013 Elsevier B.V. All rights reserved.

关键词： fluid-structure interaction Finite element method Immersed boundary method Heart valve

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fluid-structure interaction model of dynamic behavior of the discharge valve in a rotary compressor

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PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART E-JOURNAL OF PROCESS MECHANICAL ENGINEERING 2015年第4期229卷 280-289页

作者： Tan, Qin Pan, Shu-lin Feng, Quan-ke Yu, Xiao-ling Wang, Zeng-li Xi An Jiao Tong Univ Sch Energy & Power Xian 710049 Peoples R China Guangxi Univ Sch Chem & Chem Engn Nanning 530004 Peoples R China

A three-dimensional fluid-structure interaction model is proposed for the discharge valve movement in a rotary compressor. The compression chamber pressure measured by the experiment confirmed that the fluid-structure interaction model is able to predict the valve dynamic behavior precisely. To demonstrate that the fact of the discharge port being covered partly by the cylinder and the roller cannot be ignored in the valve model, another fluid-structure interaction model in which the discharge port is not covered and the cylinder shape is simplified to be cylindrical is also specially presented. In this simplified fluid-structure interaction model, the flow energy loss through the discharge valve is 68.8% of that in the fluid-structure interaction model, and the impact velocity of the valve reed impacting on the retainer is 2.9m/s higher than that in the FSI model. It is found that the valve reed is obviously inclined because the discharge port is covered partly by the cylinder.

关键词： fluid-structure interaction discharge valve rotary compressor dynamic analysis valve reed

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fluid-structure interaction Model for Predicting Surgical Result of Total Anomalous Pulmonary Venous Connection and Estimating Pulmonary Venous Properties

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CARDIOVASCULAR ENGINEERING AND TECHNOLOGY 2022年第5期13卷 725-734页

作者： Jin, Jie Ma, Xiaohui Fu, Xingpeng Zhang, Zewei Yu, Jiangen Zhejiang Univ Childrens Hosp Natl Clin Res Ctr Child Hlth Dept Cardiac SurgSch Med Hangzhou Peoples R China Zhejiang Univ Childrens Hosp Natl Clin Res Ctr Child Hlth Dept RadiolSch Med Hangzhou Peoples R China Zhejiang Univ Childrens Hosp Natl Clin Res Ctr Child Hlth Dept UltrasonogSch Med Hangzhou Peoples R China

Objectives To build a fluid-structure interaction model of pulmonary veins with total anomalous pulmonary venous connection, which can be used to predict the result of surgical treatment and at the same time to estimate the elastic properties of pulmonary veins based on patient-specific data and clinic postoperative results. Methods The fluid-structure interaction (FSI) model was used to simulate the anastomosis on pulmonary veins based on computed tomography angiography data collected from three children with total anomalous pulmonary venous connection (TAPVC), supra-cardiac type. The deformation and the stress of anastomosis, and also the velocity of blood flow were calculated in fluid-structure coupling algorithm. During the simulation the variable boundary conditions were applied, including the thickness of vessel wall and the vessel elasticity for which was selected a range of values. The calculation results were finally compared to postoperative results of same patients and discussed. The corresponding outcomes are given in the conclusions section. Results The blood flow velocity through the outlet will vary depending on the properties of vessels, including physical properties and thickness of vessel wall. The stress on vessel is lower for smaller values of Young's modulus. The calculated blood flow velocity correlates well with the postoperative results for the Young's modulus of vessels ranging from 0.5 to 1.0 MPa. Conclusions The FSI model has high potential to predict the result of surgery for TAPVC and to estimate the physical properties of pulmonary vein. This model also has potential to guide the strategy for surgical treatment.

关键词： fluid-structure interaction TAPVC Pulmonary vein Anastomosis Young's modulus

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fluid-structure interaction simulation of aortic blood flow

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COMPUTERS & fluidS 2011年第1期43卷 46-57页

作者： Crosetto, Paolo Reymond, Philippe Deparis, Simone Kontaxakis, Dimitrios Stergiopulos, Nikolaos Quarteroni, Alfio Ecole Polytech Fed Lausanne SB MATHICSE CMCS Stn 8 Lausanne Switzerland Ecole Polytech Fed Lausanne STI LHTC IBI2 Stn 15 Lausanne Switzerland Politecn Milan MOX Dept Math I-20133 Milan Italy

The numerical tools to simulate blood flow in the cardiovascular system are constantly developing due to the great clinical interest and to scientific advances in mathematical models and computational power. The present work aims to address and validate new algorithms to efficiently predict the hemodynamics in large arteries. These algorithms rely on finite elements simulation of the fluid-structure interaction between blood flow and arterial wall deformation of a healthy aorta. Different sets of boundary conditions are devised and tested. The mean velocity and pressure time evolution is plotted on different sections of the aorta and the wall shear stress distribution is computed. The results are compared with those obtained with a rigid wall simulation. Pulse wave velocity is computed and compared with the values available from the literature. The flow boundary conditions used for the outlets are obtained using the solution of a one-dimensional model. The results of the simulations are in agreement with the physiological data in terms of wall shear stress, wall displacement, pressure waveforms and velocities. (C) 2010 Elsevier Ltd. All rights reserved.

关键词： Blood flow models fluid-structure interaction Finite elements Hemodynamics

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fluid-structure interaction modeling of ringsail parachutes with disreefing and modified geometric porosity

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COMPUTATIONAL MECHANICS 2012年第6期50卷 835-854页

作者： Takizawa, Kenji Fritze, Matthew Montes, Darren Spielman, Timothy Tezduyar, Tayfun E. Waseda Univ Dept Modern Mech Engn Shinjuku Ku Tokyo 1698050 Japan Waseda Univ Waseda Inst Adv Study Shinjuku Ku Tokyo 1698050 Japan Rice Univ Houston TX 77005 USA

fluid-structure interaction (FSI) modeling of parachutes poses a number of computational challenges. These include the lightness of the parachute canopy compared to the air masses involved in the parachute dynamics, in the case of ringsail parachutes the geometric porosity created by the construction of the canopy from "rings" and "sails" with hundreds of "ring gaps" and "sail slits," in the case of parachute clusters the contact between the parachutes, and "disreefing" from one stage to another when the parachute is used in multiple stages. The Team for Advanced Flow Simulation and Modeling (T*AFSM) has been successfully addressing these computational challenges with the Stabilized Space-Time FSI (SSTFSI) technique, which was developed and improved over the years by the T*AFSM and serves as the core numerical technology, and a number of special techniques developed in conjunction with the SSTFSI technique. The quasi-direct and direct coupling techniques developed by the T*AFSM, which are applicable to cases with nonmatching fluid and structure meshes at the interface, yield more robust algorithms for FSI computations where the structure is light. The special technique used in dealing with the geometric complexities of the rings and sails is the homogenized modeling of geometric porosity (HMGP), which was developed and improved in recent years by the T*AFSM. The surface-edge-node contact tracking (SENCT) technique was introduced by the T*AFSM as a contact algorithm where the objective is to prevent the structural surfaces from coming closer than a minimum distance in an FSI computation. The recently-introduced conservative version of the SENCT technique is more robust and is now an essential technology in the parachute cluster computations carried out by the T*AFSM. As an additional computational challenge, the parachute canopy might, by design, have some of its panels and sails removed. In FSI computation of parachutes with such "modified geometric porosity," the f

关键词： fluid-structure interaction Parachutes Space-time techniques Ringsail parachutes Parachute clusters Contact Parachute disreefing

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fluid-structure interaction modeling of clusters of spacecraft parachutes with modified geometric porosity

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COMPUTATIONAL MECHANICS 2013年第6期52卷 1351-1364页

作者： Takizawa, Kenji Tezduyar, Tayfun E. Boben, Joseph Kostov, Nikolay Boswell, Cody Buscher, Austin Waseda Univ Inst Adv Study Dept Modern Mech Engn & Waseda Shinjuku Ku Tokyo 1698050 Japan Rice Univ Dept Mech Engn Houston TX 77005 USA

To increase aerodynamic performance, the geometric porosity of a ringsail spacecraft parachute canopy is sometimes increased, beyond the "rings" and "sails" with hundreds of "ring gaps" and "sail slits." This creates extra computational challenges for fluid-structure interaction (FSI) modeling of clusters of such parachutes, beyond those created by the lightness of the canopy structure, geometric complexities of hundreds of gaps and slits, and the contact between the parachutes of the cluster. In FSI computation of parachutes with such "modified geometric porosity," the flow through the "windows" created by the removal of the panels and the wider gaps created by the removal of the sails cannot be accurately modeled with the Homogenized Modeling of Geometric Porosity (HMGP), which was introduced to deal with the hundreds of gaps and slits. The flow needs to be actually resolved. All these computational challenges need to be addressed simultaneously in FSI modeling of clusters of spacecraft parachutes with modified geometric porosity. The core numerical technology is the Stabilized Space-Time FSI (SSTFSI) technique, and the contact between the parachutes is handled with the Surface-Edge-Node Contact Tracking (SENCT) technique. In the computations reported here, in addition to the SSTFSI and SENCT techniques and HMGP, we use the special techniques we have developed for removing the numerical spinning component of the parachute motion and for restoring the mesh integrity without a remesh. We present results for 2- and 3-parachute clusters with two different payload models.

关键词： fluid-structure interaction Parachutes Space-time techniques Ringsail parachutes Parachute clusters Contact Modified geometric porosity

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fluid-structure interaction in a pulmonary arterial bifurcation

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JOURNAL OF BIOMECHANICS 2007年第12期40卷 2694-2699页

作者： Yang, X. L. Liu, Y. Yang, J. M. Univ Sci & Technol China Dept Modern Mech Hefei 230027 Anhui Peoples R China Hong Kong Polytech Univ Dept Mech Engn Kowloon Hong Kong Peoples R China

A numerical method is developed to solve the fluid-structure interaction in three-dimensional pulmonary arterial bifurcation with collapsible tubes. A self-developed FEM code is used to calculate the nonlinear deformation of the thin-walled structure and a commercial CFD solver, FLUENT, is used to resolve the fluid flow. The large deformation of the structure alters the flow field significantly while the fluid pressure affects the deformation of the structure strongly. In the bifurcation branches, the relatively short tube collapses into wave number N = 3 mode. The strong collapse of the branch tube leads to a large contraction of the cross-sectional area and increases the resistance on the fluid flow. The recirculation occurs at both the up- and down-stream of the collapsed tube. (c) 2007 Elsevier Ltd. All rights reserved.

关键词： pulmonary arterial bifurcation fluid-structure interaction collapsible tubes

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fluid-structure interaction study on the causes of mending material damage after sigmoid sinus wall reconstruction

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COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2024年 245卷 108040-108040页

作者： Xu, Kaihang Qiu, Xiaoyu Dai, Chihang He, Kaixuan Wang, Guopeng Mu, Zhenxia Gao, Bin Gong, Shusheng Wang, Zhenchang Zhao, Pengfei Beijing Univ Technol Fac Environm & Life Beijing 100124 Peoples R China Capital Med Univ Beijing Friendship Hosp Dept Radiol 95 Yongan Rd Beijing 100050 Peoples R China Capital Med Univ Beijing Friendship Hosp Dept Otorhinolaryngol Head & Neck Surg 95 Yongan Rd Beijing 100050 Peoples R China Shandong First Med Univ Dept Radiol Shandong Prov Hosp Jinan 250021 Peoples R China

Background and objective: Sigmoid Sinus (SS) Wall Reconstruction (SSWR) is the mainstream treatment for pulsatile tinnitus (PT), but it has a high risk of recurrence. The damage of mending material is the key cause of recurrence, and its hemodynamic mechanism is still unclear. The purpose of this study was to investigate the hemodynamic causes of mending material breakage. Methods: In this study, six patient-specific geometric models were reconstructed based on the data of the computed tomography angiography (CTA). The transient fluid-structure coupling method was performed to clarify the hemodynamic state of sigmoid sinus and the biomechanical state of the mending material. The distribution of stress and displacement and the flow pattern were calculated to evaluate the hemodynamic and biomechanics difference at the mending material area. Results: The area of blood flow impact in some patients (2/6) was consistent with the damaged location of the mending material. The average stress (6/6) and average displacement (6/6) of damaged mending material were higher than those of complete mending material. All (6/6) patients showed that the high-stress and highdisplacement proportion of the DMM region was higher than that of the CMM region. Moreover, the average stress fluctuation (6/6) and average displacement (6/6) fluctuation degree of damaged mending material is larger than that of complete mending material. Conclusions: The impact of blood and the uneven stress and displacement fluctuation of the mending material may be the causes of mending material damage. High stress and high displacement might be the key causes of the mending material damage.

关键词： Pulsatile tinnitus Sigmoid sinus wall reconstruction Mending material damage fluid-structure interaction Biomechanical

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