DISTRIBUTION OF SHEAR STRAIN IN SQUARE CROSS-SECTION SHAFT MEASURED USING IMAGE ANALYSIS UNDER LARGE DEFORMATION

2020 ◽  
Vol 7 (2) ◽  
Author(s):  
Yasuyuki Kato
Keyword(s):  
Image Analysis ◽  
Natural Rubber ◽  
Shear Strain ◽  
Large Deformation ◽  
Cross Section ◽  
Image Data ◽  
Gauge Length ◽  
Strain Theory ◽  
Test Pieces ◽  
The Cross

In the present study, the distribution of shear strain and warping in a square cross-section shaft generated under a large torsion is investigated using the image analysis based on the Natural Strain theory. The scribe lines are drawn in a grid on a surface of the test pieces made of natural rubber, and the image data of each element in the horizontal direction along the cross-section at the center and upper positions are taken by using a high-pixel camera equipped with macro lens. The distributions for shear strain and warping along the cross-section are obtained from that image data. These measured distributions under large deformation are compared with the distributions based on the conventional torsional theory of a square cross-section shaft, i.e., Saint Venant's theory for torsion. Moreover, taking the effect due to the elongation on the surface of specimens into consideration, the distributions modified elongation of gauge length are compared with experiments, and the validity of the present experimental results are confirmed in this paper.

Automated Diagonal Slice and View Solution for 3D Device Structure Analysis

2018 ◽  
Author(s):  
Sang Hoon Lee ◽  
Jeff Blackwood ◽  
Stacey Stone ◽  
Michael Schmidt ◽  
Mark Williamson ◽  
...  
Keyword(s):  
Cross Section ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Image Data ◽  
Planar Surface ◽  
Device Structure ◽  
Cross Sectional ◽  
Device Structures ◽  
The Cross ◽  
Planar Analysis

Abstract The cross-sectional and planar analysis of current generation 3D device structures can be analyzed using a single Focused Ion Beam (FIB) mill. This is achieved using a diagonal milling technique that exposes a multilayer planar surface as well as the cross-section. this provides image data allowing for an efficient method to monitor the fabrication process and find device design errors. This process saves tremendous sample-to-data time, decreasing it from days to hours while still providing precise defect and structure data.

A Novel User-Friendly Image Analysis Technique for Determination of Electrospun Nanofibrous Mats Thickness

NANO ◽  
2017 ◽  
Vol 12 (11) ◽  
pp. 1750130 ◽  
Author(s):  
Bentolhoda Hadavi Moghadam ◽  
Shohreh Kasaei ◽  
A. K. Haghi
Keyword(s):  
Image Analysis ◽  
Cross Section ◽  
Depth Estimation ◽  
Thickness Measurement ◽  
Relative Depth ◽  
Image Analysis Technique ◽  
Analysis Technique ◽  
The Cross ◽  
User Friendly

In this study, a novel technique for measuring the thickness of electrospun nanofibrous mat based on image analysis techniques is proposed. The thicknesses of electrospun polyacrylonitrile (PAN), polyvinyl alcohol (PVA), and polyurethane (PU) nanofibrous mats are calculated using depth estimation in different views. The images are captured by a fixed scanning electron microscope (SEM) where the mat sample is rotated by 15[Formula: see text], 30[Formula: see text], and 45[Formula: see text] angles. By calculating the disparity value (the distance between two corresponding points in two images), the relative depth of images and consequently the thickness of nanofibrous mat are obtained. Furthermore, the thickness of three electrospun mats are measured from the cross-section view of the nanofibrous mat by scanning the electron microscopy. A close agreement between results obtained by this method at low angle views (15[Formula: see text]) and the direct thickness measurement obtained from the cross-section view is achieved. Comparison of the average thickness from the direct measurement and the proposed method for different samples exhibits a linear relationship with the high regression coefficient of 0.96. By using the proposed method, the quantitative evaluation of the thickness measurement becomes feasible over the entire surface of electrospun mats.

FINITE STRAIN MEASUREMENT USING IMAGE ANALYSIS UNDER REVERSE SHEAR AFTER FORWARD SHEAR

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Yasuyuki Kato
Keyword(s):  
Image Analysis ◽  
Effective Strain ◽  
Local Deformation ◽  
Gauge Length ◽  
Strain Theory ◽  
Strain Component ◽  
Deformation Path ◽  
Strain Behavior ◽  
Natural Strain ◽  
Shearing Strain

The purpose of this research is to investigate the progress of local deformation under finite deformation by using image analysis based on the Natural Strain theory. Since Natural Strain used in the image analysis can satisfy the addition law of strain on an identical line element and can remove the rigid body rotation from shearing strain component, it is an effective strain for representing stress and strain behavior under large deformation. Therefore, in this research, these features of Natural Strain theory will be incorporated into the method of image analysis. In the present study, using the test pieces made of high purity tough pitch copper, the local deformation occurring under large simple shear is investigated by comparing the strains in each element from the upper position to the middle position with the average strain in the gauge length. In order to investigate the progress of local deformation caused by differences of strain hardening in the material, the experiments are conducted under different deformation histories which are given by applying reverse shear after applying forward shear with different sizes. Consequently, it is revealed that if the value of plastic strain obtained by integrating over the whole deformation path is almost the same, the progress of local deformation is approximately the same even if the deformation path is different.

Evaluation of efficiency of methods for drawing round wire with large diameters

2021 ◽  
pp. 28-33
Author(s):  
V. A. Kharitonov ◽  
M. Yu. Usanov
Keyword(s):  
Shear Strain ◽  
Cross Section ◽  
High Energy ◽  
Production Costs ◽  
Drawing Force ◽  
Strain Inhomogeneity ◽  
Accumulated Strain ◽  
The Wire ◽  
The Cross ◽  
Deform 3D

Drawing in monolithic draw dies is the primary and often nonalternative pressure metal treatment (PMT) method used in the wire manufacture for various purposes both in our country and abroad. Its effectiveness largely depends on the wire diameter and properties. Thus, when drawing wire of large diameters (>8.0 mm) from high-carbon steels (high-tensile reinforcing wire, spring wire, etc.), the stability of the process and the probability of metal fraction decreases. The use of classic roller draw dies increases the strain uniformity along the wire cross-section, reduces the force and multiplicity of drawing. However, the «circle-shaped section-circle» roller gauge system used in this process leads to a more complicated process, and most importantly, to a significant increase in production costs. In this paper, a comparative analysis of the drawing efficiency of a round billet with a diameter of 16.00 mm from steel grade 80 into a wire with a diameter of 14.25 mm (strain degree 21%) in one step in the classic monolithic draw die and roller draw dies: three-roller draw die with a spatially closed round gauge and three-roller draw die of radial shear strain. The latter is comparable to the well-known radial-shear rolling. The difference is that the energy is introduced into the deformation zone by applying a front pulling force, and the idler rollers rotate around the wire with a special drive. The authors used finite element modeling in the Deform-3d software package. The deformed state in processes with linear tensile strain was estimated by the distribution of the accumulated strain degree in the billet cross-section, and in processes with torsion – by the change in the curvature of the line applied to the side surface of the billet. The power parameters were determined in Deform-3d in the coordinates: drawing force – time of billet movement. The stress state was determined by the hydrostatic stress on the wire axis and the Cockcroft-Latham fracture criterion. It is established that the wire strain in a monolithic draw die is characterized by a significant strain inhomogeneity across the cross-section, monotonous flow, high energy consumption, and the wire collapsibility, especially of the mid-layers. The use of draw dies with a spatially closed round gauge reduces the drawing force by about 40%, reduces the degree of strain inhomogeneity along the cross-section, and increases the degree of accumulated strain. The radial-shear strain drawing significantly increases the degree of accumulated strain and provides grain grinding, especially in the surface layers of the wire.

Estimation of carcass composition by computer image analysis in the cross sections of cross-bred steers

1996 ◽  
Vol 76 (4) ◽  
pp. 497-506 ◽  
Author(s):  
A. B. Karnuah ◽  
K. Moriya ◽  
Y. Sasaki ◽  
K. Mitani ◽  
T. Yamazaki
Keyword(s):  
Image Analysis ◽  
Cross Section ◽  
Computer Image ◽  
Correlation Coefficients ◽  
Carcass Composition ◽  
Data Sets ◽  
Computer Image Analysis ◽  
Data Set ◽  
Stepwise Procedure ◽  
The Cross

Estimation equations for carcass composition were obtained using the information extracted from the carcass cross section by Computer Image Analysis (CIA). The total kilograms of lean, fat, and bone, and their percentages, were measured on the left side of the carcasses of F1 (cross-bred between Japanese Black and Holstein) steers by physical dissection. Traced data of the cross section between the 5th and 6th ribs (Data set I) and pictures of carcass cross section between the 7th and 8th ribs (Data set II) were subjected to image analysis. Various information on both the individual muscles and the overall outline of the cross section was extracted by the CIA technique. Maximum R2 improvement method of the stepwise procedure was used to choose the best regression equation to estimate carcass composition as total kilograms and percentages of lean, fat, and bone. The data sets were also adjusted for age and the stepwise procedure was also conducted. Coefficients of determination, adjusted for the degrees of freedom (adjusted R2) of the regression equations for estimating carcass composition, were high, i.e., 0.779 to 0.959 for kilograms of lean, fat, and bone, whereas for the percentages of lean, fat, and bone were high, i.e., 0.788 to 0.952, respectively. For the adjusted data, the adjusted R2 for estimating kilograms of lean, fat, and bone with Data sets I and II were 0.729, 0.633, and 0.598, and 0.813, 0.806, and 0.878, respectively, while for the percentages of lean, fat, and bone were 0.793, 0.623, and 0.378, and 0.953, 0.989, and 0.467, respectively. When the estimation equation obtained from the unadjusted Data set I was fitted with the information extracted from Data set II, the correlation coefficients between the values estimated by the equation and the values obtained by physical dissection on carcass composition were high, ranging from 0.70 to 0.92. On the other hand, the correlation coefficients obtained from the adjusted data sets were low. Key words: Estimation equation, computer image analysis, carcass composition, carcass cross section, F1 steers

A new higher-order locking-free beam element based on the absolute nodal coordinate formulation

2017 ◽  
Vol 232 (19) ◽  
pp. 3410-3423 ◽  
Author(s):  
Haidong Yu ◽  
Chunzhang Zhao ◽  
Bin Zheng ◽  
Hao Wang
Keyword(s):  
Large Deformation ◽  
Cross Section ◽  
Absolute Nodal Coordinate Formulation ◽  
Beam Element ◽  
Higher Order ◽  
Continuity Condition ◽  
Large Rotation ◽  
Absolute Nodal Coordinate ◽  
The Absolute ◽  
The Cross

The beam elements based on the absolute nodal coordinate formulation are widely used in large deformation and large rotation problems. Some of them lead to shear and Poisson locking problems when the continuum mechanics method is employed to deduce the generalized elastic force of the element. To circumvent these locking problems, a new higher-order beam element is proposed that may capture the warping and non-uniform stretching distribution of the cross-section by introducing the trapezoidal cross-section deformation mode and increasing the order of interpolation polynomials in transverse direction. The curvature vectors are chosen as the nodal coordinates of the new element that improve the continuity condition at the element interface. Static and dynamic analyses are conducted to investigate the performance of the new element. Poisson locking phenomena may be eliminated effectively for the new element even when Poisson’s ratio is greater than zero. Meanwhile, the distortion deformation of the cross-section may be described directly. The new element has a better convergence performance compared with the spatial absolute nodal coordinate formulation beam element for that shear locking issue is eliminated. The results also show that the new element fulfills energy conservation and may be applied to the dynamics of both straight and initial curved structures with large deformation.

Generalized Algorithms for Interactive Warping Analysis of Porous Cross Sections

1999 ◽  
Author(s):  
Y. C. Pao ◽  
Erik L. Ritman
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Image Data ◽  
Ct Scanning ◽  
Iterative Solution ◽  
Coefficient Matrix ◽  
Finite Difference Approximation ◽  
Difference Approximation ◽  
Cross Sectional ◽  
The Cross

Abstract Algorithms have been developed for warping analysis and calculation of the shearing stresses in a general porous cross section of a long rod when it is subjected to twisting torques at its ends. The shape and dimensions of the cross section full of holes are defined from the binary segmented image data with by a micro-CT scanning technique. Finite difference approximation of the Laplace equation governing the cross-sectional warping leading to the matrix solution by a Gauss-Seidel process is discussed. Method of pointer matrix which keeps the locations of the nonzero elements of the coefficient matrix, is employed to expedite the iterative solution. Computer programs are coded in QuickBASIC language to facilitate plotting of the computed distributions of warping and shearing stresses. The classical torsional problem of square and thin-walled cross sections are used to reexamine the accuracy of the developed algorithms and results are found to be in very good agreement.

Coupled Deformation Modes in the Large Deformation Finite-Element Analysis: Problem Definition

2006 ◽  
Vol 2 (2) ◽  
pp. 146-154 ◽  
Author(s):  
Bassam A. Hussein ◽  
Hiroyuki Sugiyama ◽  
Ahmed A. Shabana
Keyword(s):  
Large Deformation ◽  
Cross Section ◽  
Flexible Structures ◽  
Beam Theory ◽  
Problem Definition ◽  
Beam Model ◽  
Element Analysis ◽  
Elastic Line ◽  
The Cross ◽  
Deformation Modes

In the classical formulations of beam problems, the beam cross section is assumed to remain rigid when the beam deforms. In Euler–Bernoulli beam theory, the rigid cross section remains perpendicular to the beam centerline; while in the more general Timoshenko beam theory the rigid cross section is permitted to rotate due to the shear deformation, and as a result, the cross section can have an arbitrary rotation with respect to the beam centerline. In more general beam models as the ones based on the absolute nodal coordinate formulation (ANCF), the cross section is allowed to deform and it is no longer treated as a rigid surface. These more general models lead to new geometric terms that do not appear in the classical formulations of beams. Some of these geometric terms are the result of the coupling between the deformation of the cross section and other modes of deformations such as bending and they lead to a new set of modes referred to in this paper as the ANCF-coupled deformation modes. The effect of the ANCF-coupled deformation modes can be significant in the case of very flexible structures. In this investigation, three different large deformation dynamic beam models are discussed and compared in order to investigate the effect of the ANCF-coupled deformation modes. The three methods differ in the way the beam elastic forces are calculated. The first method is based on a general continuum mechanics approach that leads to a model that includes the ANCF-coupled deformation modes; while the second method is based on the elastic line approach that systematically eliminates these modes. The ANCF-coupled deformation modes eliminated in the elastic line approach are identified and the effect of such deformation modes on the efficiency and accuracy of the numerical solution is discussed. The third large deformation beam model discussed in this investigation is based on the Hellinger–Reissner principle that can be used to eliminate the shear locking encountered in some beam models. Numerical examples are presented in order to demonstrate the use and compare the results of the three different beam formulations. It is shown that while the effect of the ANCF-coupled deformation modes is not significant in very stiff and moderately stiff structures, the effect of these modes can not be neglected in the case of very flexible structures.

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