A Novel Micro-CT Based Anatomically Accurate Finite Element Model for Simulation-Aided Assessment of Mitral Valve Repairs

2013 ◽  
Author(s):  
Chung-Hao Lee ◽  
Robert C. Gorman ◽  
Joseph H. Gorman ◽  
Rouzbeh Aimini ◽  
Michael S. Sacks
Keyword(s):  
Finite Element ◽  
Mitral Valve ◽  
Mitral Regurgitation ◽  
Constitutive Models ◽  
Element Model ◽  
Tissue Level ◽  
Cellular Level ◽  
Fe Model ◽  
Mitral Valves ◽  
Mechanical Responses

Many surgeons have come to view mitral valve (MV) repair as the treatment of choice in patients with mitral regurgitation (MR) [1]. According to recent long-term studies, the recurrence of significant MR after repair may be much higher than previously believed, particularly in patients with (ischemic mitral regurgitation) IMR [2]. We hypothesize that the restoration of homeostatic normal MV leaflet tissue stress in IMR repair techniques ultimately leads to improved repair durability. Therefore, the objective of this study is to develop a novel micro-anatomically accurate 3D finite element (FE) model that incorporates detailed collagen fiber architecture, accurate constitutive models, and micro-anatomically realistic valvular geometry to investigate the functional mitral valve and to aid in the assessment of the mitral valve repairs, especially the linking between the interstitial cellular deformations at the cellular level, the mechanobiological behaviors at the tissue level and the organ level mechanical responses as normal and repaired mitral valves maintaining their homeostatic state.

A High Fidelity, Micro-Structural and Anatomically Accurate 3D Finite Element Model for Functioning Heart Mitral Valve

2013 ◽  
Author(s):  
Chung-Hao Lee ◽  
Pim J. A. Oomen ◽  
Jean Pierre Rabbah ◽  
Neela Saikrishnan ◽  
Ajit Yoganathan ◽  
...  
Keyword(s):  
Finite Element ◽  
Mitral Valve ◽  
Mitral Regurgitation ◽  
Constitutive Models ◽  
Element Model ◽  
Suture Line ◽  
High Fidelity ◽  
Fe Model ◽  
3D Finite Element ◽  
Mechanical Responses

Many surgeons have come to view mitral valve (MV) repair as the treatment of choice in patients with mitral regurgitation (MR) [1]. However, recent long-term studies have indicated that the recurrence of significant MR after repair may be much higher than previously believed, particularly in patients with (ischemic mitral regurgitation) IMR [2]. Since a significant number of these failures result from chordal, leaflet and suture line disruption, it has been suggested that excessive tissue stress and the resulting strain-induced tissue damage are important etiologic factors. We thus hypothesize that the restoration of homeostatic normal MV leaflet tissue stress levels in IMR repair techniques ultimately leads to improved repair durability through restoration of normal MV responses. Therefore, the objective of this study is to develop a novel high-fidelity and micro-anatomically accurate 3D finite element (FE) model that incorporates detailed collagen fiber architecture, realistic constitutive models, and micro-anatomically accurate valvular geometry to connect the cellular function of the MV tissues with the organ level mechanical responses, and to aid in the design of MV repair procedures.

scholarly journals First Finite Element Model of the Left Ventricle With Mitral Valve: Insights Into Ischemic Mitral Regurgitation

2010 ◽  
Vol 89 (5) ◽  
pp. 1546-1553 ◽  
Author(s):  
Jonathan F. Wenk ◽  
Zhihong Zhang ◽  
Guangming Cheng ◽  
Deepak Malhotra ◽  
Gabriel Acevedo-Bolton ◽  
...  
Keyword(s):  
Finite Element ◽  
Mitral Valve ◽  
Left Ventricle ◽  
Mitral Regurgitation ◽  
Finite Element Model ◽  
Element Model ◽  
Ischemic Mitral Regurgitation

scholarly journals Finite Element Modeling and Physical Property Estimation of Rheological Food Objects

2012 ◽  
Vol 1 (1) ◽  
pp. 48 ◽  
Author(s):  
Zhongkui Wang ◽  
Shinichi Hirai
Keyword(s):  
Finite Element ◽  
Parameter Estimation ◽  
Estimation Method ◽  
Constitutive Models ◽  
Residual Deformation ◽  
Physical Property ◽  
Element Model ◽  
Fe Model ◽  
Step Method ◽  
Rheological Behaviors

<p>The purpose of this study is to accurately simulate the rheological behaviors of food objects undergoing a loading-unloading operation using finite element (FE) model. Due to the presence of residual deformation, it is difficult to model rheological behaviors. Especially, it is hard to accurately reproduce both rheological force and residual deformation simultaneously. In this study, objects made of food materials were tested. Force and deformation measurements were recorded for parameter estimation. Constitutive models were investigated for describing rheological behaviors. A parallel five-element model including two dual-moduli viscous elements was proposed to accurately predict both rheological force and residual deformation simultaneously. 2D/3D FE model was formulated for simulating rheological behaviors. To estimate the parameters, an effective four-step method was established based on nonlinear optimization which aimed at minimizing the differences of forces and deformation between simulation and experiments. The proposed FE model and parameter estimation method were validated in both 2D and 3D cases and good agreements were achieved in both rheological forces and deformation between numerically simulated and experimentally measured data.</p>

scholarly journals Finite element model and experimental studies on rubber-cord composite

2007 ◽  
Vol 29 (4) ◽  
pp. 551-561 ◽  
Author(s):  
Tran Huu Nam
Keyword(s):  
Finite Element ◽  
Experimental Studies ◽  
Element Model ◽  
Tensile Tests ◽  
Rubber Matrix ◽  
Uniaxial Tensile ◽  
Fe Model ◽  
Material Behaviour ◽  
Mechanical Responses ◽  
Cyclic Tension

The rubber-cord composite (CRC) which is created of rubber matrix reinforced with textile cords is used for many applications such as pneumatic membranes, automobile tires, pneumatic air-springs, hydraulic hoses and many others. The CRC is characterized by strongly anisotropic material behaviour and can simultaneously undergo large elastic deformations. In this paper a finite element (FE) model was developed and applied to study the mechanical responses of CRC. This model consists of 8-node hexahedral brick elements describing rubber matrix and 3-D spar elements for modeling of textile cords. The experimental studies in uniaxial and cyclic tension were performed. The material constants of textile cords were fitted to experimentally measured data by approach technique using linear and bilinear elastic models. The simulations of uniaxial tensile tests using proposed FE model were carried out. The numerical results of simulations were compared to experimental ones in order to verify the accurateness of the FE model. The obtained results indicated that the proposed FE model can be applied for the modeling and simulation of mechanical behaviour of CRC.

Finite Element Analysis of the Distributed Vibration Absorbers for Structural Noise Control

2005 ◽  
Author(s):  
Ashwini Gautam ◽  
Chris Fuller ◽  
James Carneal
Keyword(s):  
Finite Element ◽  
Numerical Model ◽  
Base Plate ◽  
Element Model ◽  
Fe Model ◽  
Vibration Absorbers ◽  
Element Analysis ◽  
Poroelastic Media ◽  
Hexahedral Elements ◽  
Component Models

This work presents an extensive analysis of the properties of distributed vibration absorbers (DVAs) and their effectiveness in controlling the sound radiation from the base structure. The DVA acts as a distributed mass absorber consisting of a thin metal sheet covering a layer of acoustic foam (porous media) that behaves like a distributed spring-mass-damper system. To assess the effectiveness of these DVAs in controlling the vibration of the base structures (plate) a detailed finite elements model has been developed for the DVA and base plate structure. The foam was modeled as a poroelastic media using 8 node hexahedral elements. The structural (plate) domain was modeled using 16 degree of freedom plate elements. Each of the finite element models have been validated by comparing the numerical results with the available analytical and experimental results. These component models were combined to model the DVA. Preliminary experiments conducted on the DVAs have shown an excellent agreement between the results obtained from the numerical model of the DVA and from the experiments. The component models and the DVA model were then combined into a larger FE model comprised of a base plate with the DVA treatment on its surface. The results from the simulation of this numerical model have shown that there has been a significant reduction in the vibration levels of the base plate due to DVA treatment on it. It has been shown from this work that the inclusion of the DVAs on the base plate reduces their vibration response and therefore the radiated noise. Moreover, the detailed development of the finite element model for the foam has provided us with the capability to analyze the physics behind the behavior of the distributed vibration absorbers (DVAs) and to develop more optimized designs for the same.

Finite Element Model of Human Cochlea Considering of the Helicotrema Size

2013 ◽  
Vol 456 ◽  
pp. 576-581 ◽  
Author(s):  
Li Fu Xu ◽  
Na Ta ◽  
Zhu Shi Rao ◽  
Jia Bin Tian
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Basilar Membrane ◽  
Round Window ◽  
Element Model ◽  
Oval Window ◽  
Fe Model ◽  
Cochlear Duct ◽  
Human Cochlea ◽  
Set Up

A 2-D finite element model of human cochlea is established in this paper. This model includes the structure of oval window, round window, basilar membrane and cochlear duct which is filled with fluid. The basilar membrane responses are calculated with sound input on the oval window membrane. In order to study the effects of helicotrema on basilar membrane response, three different helicotrema dimensions are set up in the FE model. A two-way fluid-structure interaction numerical method is used to compute the responses in the cochlea. The influence of the helicotrema is acquired and the frequency selectivity of the basilar membrane motion along the cochlear duct is predicted. These results agree with the experiments and indicate much better results are obtained with appropriate helicotrema size.

Finite Element Mesh Generator Applying Constraints’ Propagation and Isoparametric Mapping

1991 ◽  
Author(s):  
J. Rodriguez ◽  
M. Him
Keyword(s):  
Finite Element ◽  
Mesh Generation ◽  
Element Model ◽  
Finite Element Mesh ◽  
Fe Model ◽  
Element Analysis ◽  
Element Mesh ◽  
Mesh Generator ◽  
Generation Algorithm ◽  
Essential Input

Abstract This paper presents a finite element mesh generation algorithm (PREPAT) designed to automatically discretize two-dimensional domains. The mesh generation algorithm is a mapping scheme which creates a uniform isoparametric FE model based on a pre-partitioned domain of the component. The proposed algorithm provides a faster and more accurate tool in the pre-processing phase of a Finite Element Analysis (FEA). A primary goal of the developed mesh generator is to create a finite element model requiring only essential input from the analyst. As a result, the generator code utilizes only a sketch, based on geometric primitives, and information relating to loading/boundary conditions. These conditions represents the constraints that are propagated throughout the model and the available finite elements are uniformly mapped in the resulting sub-domains. Relative advantages and limitations of the mesh generator are discussed. Examples are presented to illustrate the accuracy, efficiency and applicability of PREPAT.

scholarly journals Use of a parametric finite element model of the mitral valve to assess healthy and pathological valve behaviors

2019 ◽  
Vol 22 (sup1) ◽  
pp. S4-S5
Author(s):  
T. Alleau ◽  
L. Lanquetin ◽  
A.-V. Salsac
Keyword(s):  
Finite Element ◽  
Mitral Valve ◽  
Finite Element Model ◽  
Element Model

scholarly journals Low Cost Frictional Seismic Base-Isolation of Residential New Masonry Buildings in Developing Countries: A Small Masonry House Case Study

2017 ◽  
Vol 11 (1) ◽  
pp. 1026-1035 ◽  
Author(s):  
Ahmad Basshofi Habieb ◽  
Gabriele Milani ◽  
Tavio Tavio ◽  
Federico Milani
Keyword(s):  
Finite Element ◽  
Seismic Vulnerability ◽  
Base Isolation ◽  
Low Cost ◽  
Element Model ◽  
Shaking Table ◽  
Fe Model ◽  
Isolation System ◽  
Finite Element Software ◽  
Non Linear

Introduction:An advanced Finite Element model is presented to examine the performance of a low-cost friction based-isolation system in reducing the seismic vulnerability of low-class rural housings. This study, which is mainly numerical, adopts as benchmark an experimental investigation on a single story masonry system eventually isolated at the base and tested on a shaking table in India.Methods:Four friction isolation interfaces, namely, marble-marble, marble-high-density polyethylene, marble-rubber sheet, and marble-geosynthetic were involved. Those interfaces differ for the friction coefficient, which was experimentally obtained through the aforementioned research. The FE model adopted here is based on a macroscopic approach for masonry, which is assumed as an isotropic material exhibiting damage and softening. The Concrete damage plasticity (CDP) model, that is available in standard package of ABAQUS finite element software, is used to determine the non-linear behavior of the house under non-linear dynamic excitation.Results and Conclusion:The results of FE analyses show that the utilization of friction isolation systems could much decrease the acceleration response at roof level, with a very good agreement with the experimental data. It is also found that systems with marble-marble and marble-geosynthetic interfaces reduce the roof acceleration up to 50% comparing to the system without isolation. Another interesting result is that there was little damage appearing in systems with frictional isolation during numerical simulations. Meanwhile, a severe state of damage was clearly visible for the system without isolation.

Studying the Intact, ACL-Deficient and Reconstructed Human Knee Joint Using a Finite Element Model

2013 ◽  
Author(s):  
Achilles Vairis ◽  
Markos Petousis ◽  
George Stefanoudakis ◽  
Nectarios Vidakis ◽  
Betina Kandyla ◽  
...  
Keyword(s):  
Finite Element ◽  
Knee Joint ◽  
Cruciate Ligament ◽  
Three Dimensional ◽  
Element Model ◽  
Human Knee ◽  
Mechanical Responses ◽  
Human Knee Joint ◽  
Calculated Load ◽  
Anterior Cruciate

The human knee joint has a three dimensional geometry with multiple body articulations that produce complex mechanical responses under loads that occur in everyday life and sports activities. Knowledge of the complex mechanical interactions of these load bearing structures is of help when the treatment of relevant diseases is evaluated and assisting devices are designed. The anterior cruciate ligament in the knee connects the femur to the tibia and is often torn during a sudden twisting motion, resulting in knee instability. The objective of this work is to study the mechanical behavior of the human knee joint in typical everyday activities and evaluate the differences in its response for three different states, intact, injured and reconstructed knee. Three equivalent finite element models were developed. For the reconstructed model a novel repair device developed and patented by the authors was employed. For the verification of the developed models, static load cases presented in a previous modeling work were used. Mechanical stresses calculated for the load cases studied, were very close to results presented in previous experimentally verified work, in both load distribution and maximum calculated load values.

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