scholarly journals The fixed-mesh ALE approach applied to solid mechanics and fluid-structure interaction problems

2009 ◽  
pp. n/a-n/a ◽  
Author(s):  
Joan Baiges ◽  
Ramon Codina
Keyword(s):  
Solid Mechanics ◽  
Fluid Structure Interaction ◽  
Fluid Structure ◽  
Structure Interaction

scholarly journals A Monolithic Approach of Fluid–Structure Interaction by Discrete Mechanics

Fluids ◽  
2021 ◽  
Vol 6 (3) ◽  
pp. 95
Author(s):  
Stéphane Vincent ◽  
Jean-Paul Caltagirone
Keyword(s):  
Solid Mechanics ◽  
Mechanical Energy ◽  
Fluid Structure Interaction ◽  
Equation Of Motion ◽  
Discrete Equation ◽  
Discrete Mechanics ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Vector Potentials

The unification of the laws of fluid and solid mechanics is achieved on the basis of the concepts of discrete mechanics and the principles of equivalence and relativity, but also the Helmholtz–Hodge decomposition where a vector is written as the sum of divergence-free and curl-free components. The derived equation of motion translates the conservation of acceleration over a segment, that of the intrinsic acceleration of the material medium and the sum of the accelerations applied to it. The scalar and vector potentials of the acceleration, which are the compression and shear energies, give the discrete equation of motion the role of conservation law for total mechanical energy. Velocity and displacement are obtained using an incremental time process from acceleration. After a description of the main stages of the derivation of the equation of motion, unique for the fluid and the solid, the cases of couplings in simple shear and uniaxial compression of two media, fluid and solid, make it possible to show the role of discrete operators and to find the theoretical results. The application of the formulation is then extended to a classical validation case in fluid–structure interaction.

An Approach on Fluid-Structure Interaction for Hemodynamics of Carotid Arteries

2012 ◽  
Author(s):  
Sang Hyuk Lee ◽  
Seongwon Kang ◽  
Nahmkeon Hur
Keyword(s):  
Blood Flow ◽  
Carotid Artery ◽  
Solid Mechanics ◽  
Fluid Structure Interaction ◽  
Blood Rheology ◽  
Numerical Approach ◽  
Patient Specific ◽  
Circulation System ◽  
Fluid Structure ◽  
Structure Interaction

In the present study, a problem of the hemodynamic fluid-structure interaction (FSI) in the carotid artery was analyzed using a numerical approach. To predict the blood flow and arterial deformation, a framework for the FSI analysis was developed by coupling computational fluid dynamics (CFD) and solid mechanics (CSM) approaches. Using this framework, the hemodynamics of the carotid artery was simulated with the patient-specific clinical data of the arterial geometry, pulsatile blood flow and blood rheology. It is found that the hemodynamic characteristics of the carotid artery are significantly affected by its geometric factors and flow conditions, and relatively low values of the wall shear stress were observed in the post-plaque dilated region of the carotid bifurcated area. Since these characteristics of the carotid artery are affected by the cerebral circulation system, the effects of the cardiac output and the distal vascular resistance on hemodynamics were also analyzed.

Adaptive Finite Elements Simulation Methods and Applications for Monolithic Fluid-Structure Interaction (FSI) Problem

2014 ◽  
Author(s):  
Bhuiyan Shameem Mahmood Ebna Hai ◽  
Markus Bause
Keyword(s):  
Fluid Dynamics ◽  
Structural Analysis ◽  
Solid Mechanics ◽  
Stokes Equations ◽  
Fluid Structure Interaction ◽  
Finite Difference Schemes ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Time Stepping ◽  
Crank Nicolson

Will an aircraft wing have the structural integrity to withstand the forces or fail when it’s racing at a full speed? Fluid-structure interaction (FSI) analysis can help you to answer this question without the need to create costly prototypes. However, combining fluid dynamics with structural analysis traditionally poses a formidable challenge for even the most advanced numerical techniques due to the disconnected, domain-specific nature of analysis tools. In this paper, we present the state-of-the-art in computational FSI methods and techniques that go beyond the fundamentals of computational fluid and solid mechanics. In fact, the fundamental rule require transferring results from the computational fluid dynamics (CFD) analysis as input into the structural analysis and thus can be time-consuming, tedious and error-prone. This work consists of the investigation of different time stepping scheme formulations for a nonlinear fluid-structure interaction problem coupling the incompressible Navier-Stokes equations with a hyperelastic solid based on the well established Arbitrary Lagrangian Eulerian (ALE) framework. Temporal discretization is based on finite differences and a formulation as one step-θ scheme, from which we can extract the implicit euler, crank-nicolson, shifted crank-nicolson and the fractional-step-θ schemes. The ALE approach provides a simple, but powerful procedure to couple fluid flows with solid deformations by a monolithic solution algorithm. In such a setting, the fluid equations are transformed to a fixed reference configuration via the ALE mapping. The goal of this work is the development of concepts for the efficient numerical solution of FSI problem and the analysis of various fluid-mesh motion techniques, a comparison of different second-order time-stepping schemes. The time discretization is based on finite difference schemes whereas the spatial discretization is done with a Galerkin finite element scheme. The nonlinear problem is solved with Newton’s method. To control computational costs, we apply a simplified version of a posteriori error estimation using the dual weighted residual (DWR) method. This method is used for the mesh adaption during the computation. The implementation using the software library package DOpElib and deal.II serves for the computation of different fluid-structure configurations.

scholarly journals A Reduced-Order Flow Model for Fluid–Structure Interaction Simulation of Vocal Fold Vibration

2019 ◽  
Vol 142 (2) ◽  
Author(s):  
Zheng Li ◽  
Ye Chen ◽  
Siyuan Chang ◽  
Haoxiang Luo
Keyword(s):  
Vocal Fold ◽  
Solid Mechanics ◽  
Flow Model ◽  
Fluid Structure Interaction ◽  
Fluid Structure ◽  
Reduced Order ◽  
New Model ◽  
Structure Interaction ◽  
Vocal Fold Vibration ◽  
Comparison Results

Abstract 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.

Simulation of Fluid-Structure Interaction of Crossflow Through a Tube Bundle and Experimental Validation

2017 ◽  
Author(s):  
Landon Brockmeyer ◽  
Jerome Solberg ◽  
Elia Merzari ◽  
Yassin Hassan
Keyword(s):  
Solid Mechanics ◽  
Tube Bundle ◽  
Fluid Structure Interaction ◽  
Spectral Element ◽  
Fluid Structure Interactions ◽  
Low Velocity ◽  
Simulation Code ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Flow Induced Vibrations

Fluid-structure interactions are complex, multi-physics phenomena of consequence for many fluid-flow domains. Modern multi-physics codes are becoming capable of simulating with great accuracy the interaction between fluid and structure dynamics. While fluid-structure interactions can occur in many forms, flow-induced vibrations are of particular interest. Such vibrations can result in the fatigue and even failure of a vibrating geometry. The prediction and minimization of flow induced vibrations are of particular importance for heat exchangers, which commonly contain bundles of tubes experiencing high-velocity crossflow. The present study simulates the fluid-structure interaction for flexibly mounted tube bundles undergoing crossflow and compares the results with experiment. The simulation code consists of a spectral-element fluid solver directly coupled with a finite-element solid mechanics solver. The fluid solver locally adapts the fluid mesh to accommodate the moving solids. In order to minimize computational expense, low Reynolds number flows are considered, allowing for a thin, pseudo 2-D domain. The flow remains laminar for the majority of the domain, with local areas of turbulence. The pins are connected to springs that supply a restorative force equivalent to the flexible mounts of the corresponding experiment. Fluid-only simulations are performed for flow spanning low to moderate velocities and compared visually with experimental flow visualizations. Coupled fluid-structure interactions are simulated with low velocity and vibration amplitudes. The measured vibration amplitudes of the simulation agree well with those of the experiment.

EFFECTS OF HYPERTENSION AND PRESSURE GRADIENT IN A HUMAN CEREBRAL ANEURYSM USING FLUID STRUCTURE INTERACTION SIMULATIONS

2017 ◽  
Vol 17 (01) ◽  
pp. 1750018 ◽  
Author(s):  
ALVARO VALENCIA ◽  
FRANCISCO TORRES
Keyword(s):  
Pressure Gradient ◽  
Cerebral Aneurysm ◽  
Solid Mechanics ◽  
Rupture Strength ◽  
Fluid Structure Interaction ◽  
Wall Stress ◽  
Von Mises Stress ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Von Mises

Fluid–structure interaction (FSI) simulations were carried out in a human cerebral aneurysm model with the objective of quantifying the effects of hypertension and pressure gradient on the behavior of fluid and solid mechanics. Six FSI simulations were conducted using a hyperelastic Mooney–Rivlin model. Important differences in wall shear stress (WSS), wall displacements, and effective von Mises stress are reported. The hypertension increases wall stress and displacements in the aneurysm region; however, the effects of hypertension on the hemodynamics in the aneurysm region were small. The pressure gradient affects the WSS in the aneurysm and also the displacement and wall stress on the aneurysm. Maximum wall stress with hypertension in the range of rupture strength was found.

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