TWO- AND THREE-DIMENSIONAL STRAIN ANALYSIS OF THE LONG ISLAND CREEK GNEISS WITH PROXIMITY TO THE ZONE OF MOST INTENSE SHEARING IN THE BREVARD ZONE IN WESTERN GEORGIA AND EASTERN ALABAMA

2020 ◽  
Author(s):  
Kathryn E. Hanson ◽  
◽  
Randy L. Kath ◽  
Robert Reid ◽  
Connor Mikilitus
Keyword(s):  
Long Island ◽  
Three Dimensional ◽  
Strain Analysis

Validation of three‐dimensional echocardiographic principal strain analysis for assessing left ventricular contractility: An animal study

2019 ◽  
Vol 46 (5) ◽  
pp. 2137-2144
Author(s):  
Sahmin Lee ◽  
Seunghyun Choi ◽  
Sehwan Kim ◽  
Yeongjin Jeong ◽  
Kyusup Lee ◽  
...  
Keyword(s):  
Animal Study ◽  
Three Dimensional ◽  
Strain Analysis ◽  
Left Ventricular ◽  
Principal Strain ◽  
Ventricular Contractility ◽  
Left Ventricular Contractility

Experimental Characterization and Finite Element Modeling of Film Capacitors for Automotive Applications

2016 ◽  
Author(s):  
D. Croccolo ◽  
T. M. Brugo ◽  
M. De Agostinis ◽  
S. Fini ◽  
G. Olmi
Keyword(s):  
Finite Element ◽  
Mechanical Response ◽  
High Reliability ◽  
Three Dimensional ◽  
Strain Analysis ◽  
Life Time ◽  
Element Model ◽  
Image Correlation ◽  
Thermal Loads ◽  
Mechanical Shock

As electronics keeps on its trend towards miniaturization, increased functionality and connectivity, the need for improved reliability capacitors is growing rapidly in several industrial compartments, such as automotive, medical, aerospace and military. Particularly, recent developments of the automotive compartment, mostly due to changes in standards and regulations, are challenging the capabilities of capacitors in general, and especially film capacitors. Among the required features for a modern capacitor are the following: (i) high reliability under mechanical shock, (ii) wide working temperature range, (iii) high insulation resistance, (iv) small dimensions, (v) long expected life time and (vi) high peak withstanding voltage. This work aims at analyzing the key features that characterize the mechanical response of the capacitor towards temperature changes. Firstly, all the key components of the capacitor have been characterized, in terms of strength and stiffness, as a function of temperature. These objectives have been accomplished by means of several strain analysis methods, such as strain gauges, digital image correlation (DIC) or dynamic mechanical analysis (DMA). All the materials used to manufacture the capacitor, have been characterized, at least, with respect to their Young’s modulus and Poisson’s ratio. Then, a three-dimensional finite element model of the whole capacitor has been set up using the ANSYS code. Based on all the previously collected rehological data, the numerical model allowed to simulate the response in terms of stress and strain of each of the capacitor components when a steady state thermal load is applied. Due to noticeable differences between the thermal expansion coefficients of the capacitor components, stresses and strains build up, especially at the interface between different components, when thermal loads are applied to the assembly. Therefore, the final aim of these numerical analyses is to allow the design engineer to define structural optimization strategies, aimed at reducing the mechanical stresses on the capacitor components when thermal loads are applied.

Abstract 224: A Deep Learning Approach to Left-Ventricular Chamber Quantification for Fully Automated Three Dimensional Strain Analysis in Cardiotoxicity

2020 ◽  
Vol 127 (Suppl_1) ◽  
Author(s):  
Bryant M Baldwin ◽  
Shane Joseph ◽  
Xiaodong Zhong ◽  
Ranya Kakish ◽  
Cherie Revere ◽  
...  
Keyword(s):  
Deep Learning ◽  
Interpolation Method ◽  
Three Dimensional ◽  
Strain Analysis ◽  
Correlation Coefficients ◽  
Semantic Segmentation ◽  
Left Ventricular ◽  
Breast Cancer Patients ◽  
Left Ventricular Chamber ◽  
Longitudinal Strains

This study investigated MRI and semantic segmentation-based deep-learning (SSDL) automation for left-ventricular chamber quantifications (LVCQ) and low longitudinal strain (LLS) determination, thus eliminating user-bias by providing an automated tool to detect cardiotoxicity (CT) in breast cancer patients treated with antineoplastic agents. Displacement Encoding with Stimulated Echoes-based (DENSE) myocardial images from 26 patients were analyzed with the tool’s Convolution Neural Network with underlying Resnet-50 architecture. Quantifications based on the SSDL tool’s output were for LV end-diastolic diameter (LVEDD), ejection fraction (LVEF), and mass (LVM) (see figure for phase sequence). LLS was analyzed with Radial Point Interpolation Method (RPIM) with DENSE phase-based displacements. LVCQs were validated by comparison to measurements obtained with an existing semi-automated vendor tool (VT) and strains by 2 independent users employing Bland-Altman analysis (BAA) and interclass correlation coefficients estimated with Cronbach’s Alpha (C-Alpha) index. F1 score for classification accuracy was 0.92. LVCQs determined by SSDL and VT were 4.6 ± 0.5 vs 4.6 ± 0.7 cm (C-Alpha = 0.93 and BAA = 0.5 ± 0.5 cm) for LVEDD, 58 ± 5 vs 58 ± 6 % (0.90, 1 ± 5%) for LVEF, 119 ± 17 vs 121 ± 14 g (0.93, 5 ± 8 g) for LV mass, while LLS was 14 ± 4 vs 14 ± 3 % (0.86, 0.2 ± 6%). Hence, equivalent LV dimensions, mass and strains measured by VT and DENSE imaging validate our unique automated analytic tool. Longitudinal strains in patients can then be analyzed without user bias to detect abnormalities for the indication of cardiotoxicity and the need for therapeutic intervention even if LVEF is not affected.

Nonhomogeneous Ventricular Wall Strain: Analysis of Errors and Accuracy

1993 ◽  
Vol 115 (4B) ◽  
pp. 497-502 ◽  
Author(s):  
Lewis K. Waldman ◽  
Andrew D. McCulloch
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Measurement Errors ◽  
Three Dimensional ◽  
Strain Analysis ◽  
Noninvasive Methods ◽  
Single Plane ◽  
Cardiac Deformation ◽  
Cardiac Strain ◽  
Element Method

Nonhomogeneous distributions of strains are simulated and utilized to determine two potential errors in the measurement of cardiac strains. First, the error associated with the use of single-plane imaging of myocardial markers is examined. We found that this error ranges from small to large values depending on the assumed variation in stretch. If variations in stretch are not accompanied by substantial regional changes in ventricular radius, the associated error tends to be quite small. However, if the nonuniform stretch field is a result of substantial variations in local curvature from their reference values, large errors in stretch and strain occur. For canine hearts with circumferential radii of 2 to 4 cm, these errors in stretch may be as great as 30 percent or more. Moreover, gradients in stretch may be over- or underestimated by as much as 100 percent. In the second part of this analysis, the influence of random measurement errors in the coordinate positions of markers on strains computed from them is studied. Arrays of markers covering about 16 cm2 of ventricular epicardium are assumed and nonuniform stretches imposed. The reference and deformed positions of the markers are perturbed with Gaussian noise with a standard deviation of 0.1 mm, and then strains are computed using either homogeneous strain theory or a nonhomogeneous finite element method. For the strain distributions prescribed, it is found that the finite element method reduces the error resulting from noise by about 50 percent over most of the region. Accurate measurements of cardiac strain distributions are needed for correlation with and validation of realistic three-dimensional stress analyses of the heart. Moreover, with the advent of increasingly effective noninvasive methods to measure cardiac deformation such as magnetic resonance imaging, the use of nonhomogeneous strain analysis to determine more accurate strain distributions has increasing clinical significance.

Constitutive Relations of Concrete under Plane Stresses Based on Generalized Octahedral Theory

2011 ◽  
Vol 71-78 ◽  
pp. 342-352
Author(s):  
Jian Hui Yang ◽  
Rong Ling Sun ◽  
Zheng Hao Yang ◽  
Xin Yang Lin ◽  
Hai Cheng Niu
Keyword(s):  
Constitutive Relations ◽  
Three Dimensional ◽  
Strain Analysis ◽  
Stress Space ◽  
Triaxial Stress State ◽  
Characteristic Element ◽  
True Triaxial ◽  
True Triaxial Stress ◽  
Strength Models ◽  
Strain Space

Continuous (or generalized) octahedral element bodies can be obtained by intercepting a cube with three groups of failure (or yield) planes successively under true triaxial stress state, on which the stresses are twin stresses. Among the resulting polyhedral characteristic element bodies, isoclinal octahedron and orthogonal octahedron are of particular importance. Strength models of continuous octahedrons are then derived by stress analysis to arbitrary inclined sections in three dimensional stress space, and strain models by the principle of strain analysis, so the plane constitutive relations of concrete can be understood by plane problems transformed by stress-strain space according to the symmetry of an orthogonal octahedral octahedron where an arbitrary oblique plane is parallel to one of three rectangular coordinate axes.

Three-Dimensional Strain-Based Model for the Severity Characterization of Dented Pipelines

2018 ◽  
Vol 1 (3) ◽  
Author(s):  
Chike Okoloekwe ◽  
Muntaseer Kainat ◽  
Doug Langer ◽  
Sherif Hassanien ◽  
J.J. Roger Cheng ◽  
...  
Keyword(s):  
Oil And Gas ◽  
Numerical Models ◽  
Three Dimensional ◽  
Strain Analysis ◽  
Computation Time ◽  
Order Continuity ◽  
Element Analysis ◽  
The Mathematical Model ◽  
Derivatives Of

Oil and gas pipelines traverse long distances and are often subjected to mechanical forces that result in permanent distortion of its geometric cross section in the form of dents. In order to prioritize the repair of dents in pipelines, dents need to be ranked in order of severity. Numerical modeling via finite element analysis (FEA) to rank the dents based on the accumulated localized strain is one approach that is considered to be computationally demanding. In order to reduce the computation time with minimal effect to the completeness of the strain analysis, an approach to the analytical evaluation of strains in dented pipes based on the geometry of the deformed pipe is presented in this study. This procedure employs the use of B-spline functions, which are equipped with second-order continuity to generate displacement functions, which define the surface of the dent. The strains associated with the deformation can be determined by evaluating the derivatives of the displacement functions. The proposed technique will allow pipeline operators to rapidly determine the severity of a dent with flexibility in the choice of strain measure. The strain distribution predicted using the mathematical model proposed is benchmarked against the strains predicted by nonlinear FEA. A good correlation is observed in the strain contours predicted by the analytical and numerical models in terms of magnitude and location. A direct implication of the observed agreement is the possibility of performing concise strain analysis on dented pipes with algorithms relatively easy to implement and not as computationally demanding as FEA.

Three-dimensional right ventricular shape and strain in congenital heart disease patients with right ventricular chronic volume loading

2020 ◽  
Author(s):  
Pamela Moceri ◽  
Nicolas Duchateau ◽  
Stéphane Gillon ◽  
Lolita Jaunay ◽  
Delphine Baudouy ◽  
...  
Keyword(s):  
Congenital Heart Disease ◽  
Heart Disease ◽  
Right Ventricular ◽  
Congenital Heart ◽  
Three Dimensional ◽  
Pulmonary Regurgitation ◽  
Strain Analysis ◽  
Local Analysis ◽  
Volume Loading ◽  
Rv Function

Abstract Aims Right ventricular (RV) function assessment is crucial in congenital heart disease patients, especially in atrial septal defect (ASD) and repaired Tetralogy of Fallot (TOF) patients with pulmonary regurgitation (PR). In this study, we aimed to analyse both 3D RV shape and deformation to better characterize RV function in ASD and TOF-PR. Methods and results We prospectively included 110 patients (≥16 years old) into this case–control study: 27 ASD patients, 28 with TOF, and 55 sex- and age-matched healthy controls. Endocardial tracking was performed on 3D transthoracic RV echocardiographic sequences and output RV meshes were post-processed to extract local curvature and deformation. Differences in shape and deformation patterns between subgroups were quantified both globally and locally. Curvature highlights differences in RV shape between controls and patients while ASD and TOF-PR patients are similar. Conversely, strain highlights differences between controls and TOF-PR patients while ASD and controls are similar [global area strain: −31.5 ± 5.8% (controls), −34.1 ± 7.9% (ASD), −24.8 ± 5.7% (TOF-PR), P < 0.001, similar significance for longitudinal and circumferential strains]. The regional and local analysis highlighted differences in particular in the RV free wall and the apical septum. Conclusion Chronic RV volume loading results in similar RV shape remodelling in both ASD and TOF patients while strain analysis demonstrated that RV strain is only reduced in the TOF group. This suggests a fundamentally different RV remodelling process between both conditions.

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