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Dynamic analysis of multi-DOF acoustic resonant system involving highly viscous fluids based on fluid-structure interaction

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JOURNAL OF SOUND AND VIBRATION 2024年 585卷

作者： Zhan, Xiaobin Yu, Lei Shi, Tielin Huazhong Univ Sci & Technol Sch Mech Sci & Engn Luoyu Rd Wuhan 430074 Peoples R China

This paper investigates the dynamic characteristics of a multi-degree-of-freedom (multi-DOF) acoustic resonant system involving highly viscous fluids. First, a fluid-structure interaction (FSI) model is established to describe the interaction between the multi-DOF acoustic resonant system and the two-phase fluids, and then the effects of various excitation parameters on the dynamic response of the coupled system are studied. Under the influence of vertical acoustic vibration, the fluid in the container undergoes violent and irregular motions, which leads to a decrease and fluctuation in the equivalent mass of the fluid. The reduction in fluid equivalent mass causes the excitation frequency to deviate from the natural frequency of the multi-DOF acoustic resonant system, thus significantly reducing the dynamic response of the coupled system. Furthermore, the fluctuation of the fluid equivalent mass induces a quasi-periodic motion pattern of the acoustic resonant system. Although increasing the excitation amplitude can effectively increase the dynamic response of the coupled system, it can also increase the fluctuation level of the dynamic response to a certain extent. By appropriately increasing the excitation frequency, the coupled system can operate at a new resonant frequency, thereby reducing the influence of fluid motion on the dynamic response of the system.

关键词： Dynamic analysis fluid-structure interaction fluid mixing Acoustic resonance Numerical simulation

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Numerical modeling of the fluid-structure interaction during blood flow in a flexible stenotic aorta

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INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER 2024年 158卷

作者： Issakhov, Alibek Sabyrkulova, Aidana Abylkassymova, Aizhan Kazakh British Tech Univ Alma Ata Kazakhstan Al Farabi Kazakh Natl Univ Alma Ata Kazakhstan

The aim of this study is to understand the relationship between blood flow and vascular mechanics in stenotic and healthy arteries and use this understanding to improve the accuracy of computational models for predicting blood flow in human arteries. The article considers four models: a flexible and rigid model of a healthy artery and two flexible arteries with stenoses of various shapes. The deformation of a blood vessel is modeled as a fluidstructure interaction (FSI). The arterial wall is modeled as an isotropic, linearly elastic material, and wall shear stress (WSS) is calculated in order to explore the correlation between induced flow stress and the shape of the artery geometry. Blood is considered as an incompressible non-Newtonian fluid, described by the Carreau viscosity model. Signals of physiological pressure and velocity are used as boundary conditions, which ensure the pulsating nature of the flow. Numerical results show that the developed model predicts vessel deformations and describes their influence on pressure distribution, pressure drop and wall shear stresses. The results of the healthy FSI model are compared with the results of the rigid wall model in order to evaluate the effect of wall elasticity on wall shear stress distribution. Thus, under pathological conditions, the maximum speed value was observed in the model with 40% stenosis and reached 2.16 m/s, while the model with 30% stenosis had a speed of 2.06 m/s. In this case, the maximum displacement of the walls during the cardiac cycle was observed in the artery with 40% stenosis. The deformation value exceeded the wall thickness by 3.3 times and reached 1.66 mm.

关键词： Numerical simulation fluid-structure interaction Pulsatile Arterial stenosis Wall shear stress Aorta Flexible wall

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Effects of body posture on aortic valve hemodynamics and biomechanics using the fluid-structure interaction method

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JOURNAL OF BIOMECHANICS 2024年 177卷 112388-112388页

作者： Shu, Peng Li, Daochun Zhao, Shiwei Lv, Rui Beihang Univ Sch Aeronaut Sci & Engn Beijing Peoples R China

Bioprosthetic heart valve (BHV), the most widely and commonly used valves in clinical practice, are susceptible to fatigue damage. Biological valves are always in one or fewer body postures before sampling in pigs and bovines. Nevertheless, human body positions are far more than them. Variations in body position significantly affect the intrinsic environment of blood pressure (BP), heart rate (HR), and peripheral resistance (PR). Such boundary condition changes will inevitably affect the implanted biological valve. In this paper, the immersed boundary method was used to simulate the motion of the aortic valve during the entire cardiac cycle in five postural blood flow environments: upright, sitting, prone, supine and orthostatic hypotension (OH). Several hemodynamic and biomechanical parameters, including the transvalvular pressure gradient and valve displacement, were evaluated. The results showed that the OH group exhibited the worst performance of the valves, accompanied by the greatest regurgitation and high-frequency flutter, predisposing patients to thrombosis and fatigue calcification. For BHVs to serve longer, patients implanted with BHV should avoid OH in their daily routine.

关键词： Postural, Aortic valve fluid-structure interaction Hemodynamics Biomechanics

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Topology optimization of stationary fluid-structure interaction problems considering a natural frequency constraint for vortex-induced vibrations attenuation

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FINITE ELEMENTS IN ANALYSIS AND DESIGN 2024年 234卷

作者： Siqueira, L. O. Silva, K. E. S. Silva, E. C. N. Picelli, R. Univ Sao Paulo Polytech Sch Dept Mechatron & Mech Syst Engn Ave Prof Mello Moraes BR-05508030 Sao Paulo Brazil Univ Sao Paulo Polytech Sch Dept Naval Architecture & Ocean Engn Ave Prof Mello Moraes BR-05508030 Sao Paulo Brazil

Topology optimization applied to fluid-structure interaction problems is challenging because the physical phenomenon in real engineering applications is usually transient and strongly coupled. This leads to costly solutions for the forward and adjoint problems, the computational bottleneck of the topology optimization method. Thus, this paper proposes a topology optimization problem formulated in the steady state with post-processing and verification in the transient state. The objective is to design a stiff structure with lower effects of vibrations induced by the transient fluid vortices. For that, the compliance minimization problem is solved subject to a natural frequency constraint (without any volume constraint). The TOBS-GT (Topology Optimization of Binary structures with geometry trimming) method is used to solve the problem. To observe the vortex-shedding around the structure, a transient simulation is performed considering an incompressible fluid flow under a laminar regime and the structure subject to large displacements. For topology optimization, the fluid flow is at a steady state and the structure is modeled considering small displacements, i.e., a one-way coupled analysis. The finite element method is used to solve the governing equations and obtain the direct/adjoint sensitivities for the compliance and natural frequency functions. In this approach, the natural frequency of the structure is shifted away from the fluid flow vortex-shedding frequency, avoiding resonance. Numerical examples show that the proposed method can be effectively applied to design 2D structures in FSI problems with lower effects of Flow-Induced Vibration, attenuating the levels of displacement at the analyzed points of the structure.

关键词： Topology optimization fluid-structure interaction Binary design variables Vibration Vortex-shedding

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Simulation Analysis and Experimental Investigation on the fluid-structure interaction Vibration Characteristics of Aircraft Liquid-Filled Pipelines under the Superimposed Impact of External Random Vibration and Internal Pulsating Pressure

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APPLIED SCIENCES-BASEL 2024年第17期14卷 8008页

作者： Zhu, Lei Chen, Chang Jiang, Yu Natl Univ Def Technol Adm & Support Dept Changsha 410073 Peoples R China Natl Univ Def Technol Coll Intelligence Sci & Technol Changsha 410073 Peoples R China

This paper investigated the fluid-structure interaction vibration response of an aircraft liquid-filled pipeline under external random vibration and internal pulsating pressure. First, the fluid-structure interaction solution is theoretically analyzed, and the advantages and disadvantages of the direct coupling method and the separation coupling method are compared, with the latter chosen as the simulation analysis method in this study. Second, taking the U-shaped oil pipeline of an aircraft engine as an example, simulation modeling was performed to compare and analyze the fluid-structure interaction vibration response of aircraft liquid-filled pipelines under different working conditions, obtaining the vibration response characteristics of stress danger points under various conditions. Finally, a test bench for an aircraft liquid-filling pipeline was built to explore the influence of external random vibrations with different kurtoses, different pipe wall thicknesses and different working conditions on the vibration response danger points of aircraft liquid-filling pipelines, verifying the simulation conclusions and providing a basis for aircraft liquid-filling pipeline design.

关键词： fluid-structure interaction vibration characteristics aircraft liquid-filled pipeline

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Thrombogenic Risk Assessment of Transcatheter Prosthetic Heart Valves Using a fluid-structure interaction Approach

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COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2024年 257卷 108469-108469页

作者： Baylous, Kyle Kovarovic, Brandon Paz, Rodrigo R. Anam, Salwa Helbock, Ryan Horner, Marc Slepian, Marvin Bluestein, Danny SUNY Stony Brook Dept Biomed Engn Stony Brook NY 11794 USA ANSYS Inc 7374 Las Positas Rd Livermore CA 94551 USA CONICET IMIT Corrientes Argentina ANSYS Inc Canonsburg PA USA Univ Arizona Sarver Heart Ctr Dept Med & Biomed Engn Tucson AZ 85721 USA

Background and Objective: Prosthetic heart valve interventions such as TAVR have surged over the past decade, but the associated complication of long-term, life-threatening thrombotic events continues to undermine patient outcomes. Thus, improving thrombogenic risk analysis of TAVR devices is crucial. In vitro studies for thrombogenicity are typically difficult to perform. However, revised ISO testing standards include computational testing for thrombogenic risk assessment of cardiovascular implants. We present a fluid-structure interaction (FSI) approach for assessing thrombogenic risk of transcatheter aortic valves. Methods: An FSI framework was implemented via the incompressible computational fluid dynamics multi-physics solver of the ANSYS LS-DYNA software. The numerical modeling approach for flow analysis was validated by comparing the derived flow rate of the 29 mm CoreValve device from benchtop testing and orifice areas of commercial TAVR valves in the literature to in silico results. Thrombogenic risk was analyzed by computing stress accumulation (SA) on virtual platelets seeded in the flow fields via ANSYS EnSight. The integrated FSIthrombogenicity methodology was subsequently employed to examine hemodynamics and thrombogenic risk of TAVR devices with two approaches: 1) engineering optimization and 2) clinical assessment. Results: Simulated effective orifice areas for commercial valves were in reported ranges. In silico cardiac output and flow rate during the positive pressure differential period matched experimental results by approximately 93 %. The approach was used to analyze the effect of various TAVR leaflet designs on hemodynamics, where platelets experienced instantaneous stresses reaching around 10 Pa. Post-TAVR deployment hemodynamics in patient-specific bicuspid aortic valve anatomies revealed varying degrees of thrombogenic risk with the highest median SA around 70 dyn & sdot;s/cm2- nearly double the activation threshold- despite those being cli

关键词： TAVR fluid-structure interaction Thrombus Cardiovascular implants Thrombogenic risk Heart valves

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COMPUTATIONAL fluid-structure interaction SIMULATION OF HEMODYNAMICS OF ARTERIOVENOUS FISTULA

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JOURNAL OF MECHANICS IN MEDICINE AND BIOLOGY 2024年第3期24卷 2350047-2350047页

作者： Shembekar, Suraj Zodpe, Dhananjay Padole, Pramod Visvesvaraya Natl Inst Technol Dept Mech Engn Nagpur 440010 India

The objective of this study is to show how important a compliant wall technique is in simulating non-Newtonian and pulsatile blood flows in arteriovenous fistula (AVF). The three-dimensional idealized geometry is used to investigate the local hemodynamics in the end-to-side, radio-cephalic AVF using computational fluid-stricture interaction (FSI) simulation. The third-order Yeoh law is used to model the behavior of the hyperelatic vessel walls. Hemodynamic parameters such as velocity, wall shear stress (WSS), oscillatory shear index (OSI), vorticity, and venous outflow rate are calculated. The results extracted for WSS on comparison of rigid and compliance wall, rigid wall WSS are 45-48.5% larger values than the compliance wall. The difference between compliance wall and rigid wall OSI is 11.5% and the rigid wall is a 10.86% decrease in compliance wall. The difference between the rigid wall AVF vorticity and the compliance wall vorticity is 18.34%, and the vorticity in the compliance wall is a 20.2% increase over the rigid wall. Maximum principle stress occurs at anastomosis (1335Pa) and 507Pa, 93Pa on vein and artery, respectively. Finally, we conclude that the artery bed and heel of AVF are prone areas of Intimal Hyperplasia. The structural result shows the tendency of the inflammation pattern of the vein required for AVF maturation. ANSYS is a highly effective commercial tool for modeling real-world problems and performing multi-physics numerical simulations.

关键词： fluid-structure interaction arteriovenous fistula computational fluid dynamics wall shear stress hemodialysis

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The fluid-structure interaction response of composite auxetic re-entrant honeycomb structures to underwater impact

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THIN-WALLED structureS 2024年 196卷

作者： Liu, Jiayi He, Xiaolong Liu, Zhikang Cao, Xiaoming Yu, Sheng Huang, Wei Huazhong Univ Sci & Technol Sch Naval Architecture & Ocean Engn Wuhan 430074 Peoples R China Hubei Key Lab Naval Architecture & Ocean Engn Hydr Wuhan 430074 Peoples R China Wuhan Second Ship Design & Res Inst Wuhan 430064 Peoples R China

In this paper, the effects of the gradient form, peak pressure and decaying time on the fluid-structure interaction of composite auxetic re-entrant honeycomb structures was experimentally and numerically investigated. The specimens for this experiment were manufactured by hot-press molding method. The acrylic transparent tube was utilized to accommodate water medium, pistons and specimen during experiment. The exponential decaying shock wave was simulated by accelerating the fly plate to impact the piston based on the one-stage light gas gun system. The incident velocity of the fly plate and process of the fluid-structure interaction response were monitored by high frame rate camera. In addition, the velocity of the shock wave in water was measured by transducers installed at different measuring points. The voltage signal of the dynamic overpressure collected by transducers was amplified by the charge amplifier and recorded by the oscilloscope. On the other hand, finite element software Abaqus/Explicit was applied to simulate the cavitation process of water domain and dynamic response of specimens. The experimental results and numerical results were in good agreement. The results indicated that the increase of the thickness of the fly plate had a certain effect on the propagation velocity of the shock wave, and the increase of the peak pressure would make the cavitation generation position close to the fluid-structure interface and make the cavitation duration longer. And the average structure which has a minimum transformation of 8.12 mm shows better underwater impact resistance than the gradient structure.

关键词： Underwater impact fluid-structure interaction Re-entrant honeycomb core Shock wave Cavitation

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Reduced-order model of geometrically nonlinear flexible structures for fluid-structure interaction applications

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INTERNATIONAL JOURNAL OF NON-LINEAR MECHANICS 2024年 158卷

作者： Flament, T. Deu, J. -F. Placzek, A. Balmaseda, M. Tran, D. -M. Univ Paris Saclay DAAA ONERA F-92322 Chatillon France HESAM Univ LMSSC Cnam EA4626 F-75003 Paris France Univ Paris Saclay DAAA ONERA F-92190 Meudon France

This paper deals with the numerical computation, via a reduced order models (ROM), of the vibrations of geometrically nonlinear structures triggered by the aeroelastic coupling with a fluid flow. The formulation of the ROM proposed in this paper is based on the projection on a basis of reduced dimension enhanced with dual modes. An explicit expression of the projected nonlinear forces is computed in a non-intrusive way based on the Implicit Condensation method. The resulting ROM is an improvement of the classical ICE method since the effects of membrane stretching are taken into account in the resolution of the dynamic equation of motion. Such a ROM aims to be adapted to follower aerodynamic unsteady loads. The construction of the ROM is first detailed and validated under several load cases on a Euler-Bernoulli beam with von Karman hypothesis. Then a fluid-structure partitioned coupling on a two-dimensional example involving vortex-induced vibrations is considered to demonstrate the capability of such ROM to replace a nonlinear FE solver. In this paper, the limitations of the ICE method are highlighted in the examples treated, while the ROM proposed overcomes such limitations and captures accurately the dynamics.

关键词： Computational dynamics Geometric nonlinearity Nonlinear model order reduction fluid-structure interaction Aeroelasticity Dual modes Euler-Bernoulli/von Karman beam

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A finite element framework for fluid-structure interaction of turbulent cavitating flows with flexible structures

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COMPUTERS & fluidS 2024年 277卷

作者： Darbhamulla, Nihar B. Jaiman, Rajeev K. Univ British Columbia Dept Mech Engn Vancouver BC V6T 1Z4 Canada

We present a finite element framework for the numerical prediction of cavitating turbulent flows interacting with flexible structures. The vapor-fluid phases are captured through a homogeneous mixture model, with a scalar transport equation governing the spatio-temporal evolution of cavitation dynamics. High-density gradients in the two-phase cavitating flow motivate the use of a positivity-preserving Petrov-Galerkin stabilization method in the variational framework. A mass transfer source term introduces local compressibility effects arising as a consequence of phase change. The turbulent fluid flow is modeled through a dynamic subgrid-scale method for large eddy simulations. The flexible structure is represented by a set of eigenmodes, obtained through a modal decomposition of the linear elasticity equations. While a partitioned iterative approach is adopted to couple the structural dynamics and cavitating fluid flow, the deforming flow domain is described by an arbitrary Lagrangian-Eulerian frame of reference. We establish the fidelity of the proposed framework by comparing it against experimental and numerical studies for both rigid and flexible hydrofoils in cavitating flows. Under unstable partial cavitating conditions, we identify specific vortical structures leading to cloud cavity collapse. We further explore features of cavitating flow past a rigid body such as re-entrant jet and turbulence-cavity interactions during cloud cavity collapse. Based on the validation study conducted over a flexible NACA66 rectangular hydrofoil, we elucidate the role of cavity and vortex shedding in governing the structural dynamics. Subsequently, we identify a broad spectrum frequency band whose central peak does not correlate to the frequency content of the cavitation dynamics or the natural frequencies of the structure, indicating the induction of unsteady flow patterns around the hydrofoil. Finally, we discuss the coupled fluid- structure dynamics during a cavitation cycle

关键词： fluid-structure interaction Cavitation Stabilized finite element Partitioned iterative Large eddy simulation Flexible hydrofoil

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