Evaluation of Analytic Estimates of Ventricular Wall Stress Using the Finite Element Method

2008 ◽  
Author(s):  
Christopher M. Ingrassia ◽  
Shantanu Y. Jani ◽  
Kevin D. Costa
Keyword(s):  
Finite Element ◽  
Circumferential Stress ◽  
Wall Stress ◽  
Cardiac Mechanics ◽  
Ventricular Wall ◽  
The Finite Element Method ◽  
Regional Wall ◽  
Circumferential Wall Stress ◽  
Theoretical Assumptions ◽  
Accurate Quantification

The importance of ventricular wall stress to cardiac function has been well-documented [1, 2], although accurate quantification remains a challenge. In this study, three popular analytic formulas for estimating circumferential wall stress were comprehensively evaluated to identify the conditions for which their use may be appropriate. In particular, the equations of Laplace [3], Mirsky [4], and Janz [5] are commonly used in the fields of cardiology and echocardiography; despite the inaccuracy of key theoretical assumptions, they have been attractive for their simplicity. For validation, we employed specialized finite element methods, developed specifically for cardiac mechanics applications [6], to compute regional wall stress in a series of model chambers having systematically varying geometric and material complexity. We limited our analysis to circumferential stress for consistency with the theoretical equations, and because of its relevance to cardiac mechanics.

scholarly journals Left ventricular regional wall curvedness and wall stress in patients with ischemic dilated cardiomyopathy

2009 ◽  
Vol 296 (3) ◽  
pp. H573-H584 ◽  
Author(s):  
Liang Zhong ◽  
Yi Su ◽  
Si-Yong Yeo ◽  
Ru-San Tan ◽  
Dhanjoo N. Ghista ◽  
...  
Keyword(s):  
Dilated Cardiomyopathy ◽  
Myocardial Infarct ◽  
Three Dimensional ◽  
Wall Stress ◽  
Cardiac Mechanics ◽  
Normal Subjects ◽  
Left Ventricular ◽  
Regional Wall ◽  
Significant Difference ◽  
Systolic Wall Stress

Geometric remodeling of the left ventricle (LV) after myocardial infarction is associated with changes in myocardial wall stress. The objective of this study was to determine the regional curvatures and wall stress based on three-dimensional (3-D) reconstructions of the LV using MRI. Ten patients with ischemic dilated cardiomyopathy (IDCM) and 10 normal subjects underwent MRI scan. The IDCM patients also underwent delayed gadolinium-enhancement imaging to delineate the extent of myocardial infarct. Regional curvedness, local radii of curvature, and wall thickness were calculated. The percent curvedness change between end diastole and end systole was also calculated. In normal heart, a short- and long-axis two-dimensional analysis showed a 41 ± 11% and 45 ± 12% increase of the mean of peak systolic wall stress between basal and apical sections, respectively. However, 3-D analysis showed no significant difference in peak systolic wall stress from basal and apical sections ( P = 0.298, ANOVA). LV shape differed between IDCM patients and normal subjects in several ways: LV shape was more spherical (sphericity index = 0.62 ± 0.08 vs. 0.52 ± 0.06, P < 0.05), curvedness at end diastole (mean for 16 segments = 0.034 ± 0.0056 vs. 0.040 ± 0.0071 mm−1, P < 0.001) and end systole (mean for 16 segments = 0.037 ± 0.0068 vs. 0.067 ± 0.020 mm−1, P < 0.001) was affected by infarction, and peak systolic wall stress was significantly increased at each segment in IDCM patients. The 3-D quantification of regional wall stress by cardiac MRI provides more precise evaluation of cardiac mechanics. Identification of regional curvedness and wall stresses helps delineate the mechanisms of LV remodeling in IDCM and may help guide therapeutic LV restoration.

Left Ventricular Wall Stress in Patients With Severe Aortic Insufficiency With Finite Element Analysis

2006 ◽  
Vol 82 (3) ◽  
pp. 840-846 ◽  
Author(s):  
Jason R. Wollmuth ◽  
Douglas R. Bree ◽  
Brian P. Cupps ◽  
Marc D. Krock ◽  
Benjamin J. Pomerantz ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Wall Stress ◽  
Aortic Insufficiency ◽  
Left Ventricular ◽  
Left Ventricular Wall ◽  
Ventricular Wall ◽  
Element Analysis

Nonlinear Incompressible Finite Element for Simulating Loading of Cardiac Tissue—Part II: Three Dimensional Formulation for Thick Ventricular Wall Segments

1988 ◽  
Vol 110 (1) ◽  
pp. 62-68 ◽  
Author(s):  
A. Horowitz ◽  
I. Sheinman ◽  
Y. Lanir
Keyword(s):  
Finite Element ◽  
Cardiac Tissue ◽  
Large Deformations ◽  
Three Dimensional ◽  
Shear Stiffness ◽  
Cardiac Mechanics ◽  
Nonlinear Finite Element ◽  
Constitutive Law ◽  
Ventricular Wall ◽  
Collagenous Matrix

A three dimensional incompressible and geometrically as well as materially nonlinear finite element is formulated for future implementation in models of cardiac mechanics. The stress-strain relations in the finite element are derived from a recently proposed constitutive law which is based on the histological composition of the myocardium. The finite element is formulated for large deformations and considers incompressibility by introducing the hydrostatic pressure as an additional variable. The results of passive loading cases simulated by this element allow to analyze the mechanical properties of ventricular wall segments, the main of which are that the circumferential direction is stiffer than the longitudinal one, that its shear stiffness is considerably lower than its tensile and compressive stiffness, and that, due to its mechanically prominent role, the collagenous matrix may affect the myocardial perfusion.

Cardiac mechanics

2020 ◽  
pp. 53-72
Author(s):  
Stephen Huang
Keyword(s):  
Left Ventricular Pressure ◽  
Wall Stress ◽  
Cardiac Mechanics ◽  
Left Ventricular ◽  
Physical Factors ◽  
Ventricular Wall ◽  
Ventricular Contractility ◽  
Intrinsic Properties ◽  
Extrinsic Factors ◽  
Cardiac Pump Function

Cardiac mechanics involves the study of the mechanical properties of the heart (ventricles) as a pump, and the physical factors that alter these properties. Neurohumoral factors aside, the function of the heart is determined by its intrinsic physical properties as well as extrinsic physical factors. The intrinsic properties include ventricular wall stress, elastance (stiffness) of the ventricle, contractility, and heart rate. The main extrinsic physical factors are blood volume, vessels properties, and extracardiac pressures. This chapter will review these intrinsic properties and how they interact with extrinsic factors to alter the cardiac (pump) function. Neurohumoral factors are excluded in this consideration. LaPlace’s law will be introduced to explain the idea of ventricular wall stress, hence the concepts of preload and afterload. The left ventricular pressure–volume relationship will be reviewed to explain how preload, afterload, and ventricular contractility interact and affect stroke volume. Finally, for completeness, the Frank–Starling relationship and Guyton’s venous return graph will be covered to explain steady state cardiac output.

Loading and Axial Deformation of Finite Element Analysis of Down-Hole Strings Used for Hydraulic Fracturing

2013 ◽  
Vol 318 ◽  
pp. 3-6 ◽  
Author(s):  
Ding Feng ◽  
Ao Xiao ◽  
Zuo Jie Liao ◽  
Yu Xie ◽  
Chao Ruan ◽  
...  
Keyword(s):  
Finite Element ◽  
Axial Stress ◽  
Circumferential Stress ◽  
Actual Condition ◽  
Axial Deformation ◽  
The Finite Element Method ◽  
Element Analysis ◽  
Squeeze Pressure ◽  
Temperature Load ◽  
The Relationship

The string is loaded by ground thermal stress, fluid squeeze pressure and gravity in horizontal wells in the process of fracturing. The fluid-solid heat coupling theory is used to make the theoretical feasibility analysis on the column simulation of the fracturing string. Fracturing string is analyzed on the suitable physical model which is set parameters, boundary conditions and constraints on the basis of actual condition by the finite element method. And it is made by different formation temperature load coupling analysis. The tubing analysis focuses on axial stress, axial deformation, and the relationship between axial stress and circumferential stress. So, it obtains the change rules of string in the process of fracturing which directly compared results of the theoretical calculation of the force produced by the axial deformation. It proves the feasibility of this method. So the paper provides a basis for guiding the production process of fracturing string, which can improve the effect of fracturing operation.

Simulation of tuning graphene plasmonic behaviors by ferroelectric domains for self-driven infrared photodetector applications

Nanoscale ◽  
2019 ◽  
Vol 11 (43) ◽  
pp. 20868-20875 ◽  
Author(s):  
Junxiong Guo ◽  
Yu Liu ◽  
Yuan Lin ◽  
Yu Tian ◽  
Jinxing Zhang ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Interfacial Effect ◽  
Infrared Photodetector ◽  
The Finite Element Method ◽  
Ferroelectric Domains ◽  
Element Method

We propose a graphene plasmonic infrared photodetector tuned by ferroelectric domains and investigate the interfacial effect using the finite element method.

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