Line strain representation and shear strain representation of 3D strain states

The strain state in 3D space is usually expressed by the conventional method of combining three linear and shear strains. Due to the obvious differences between the first two strains, it is necessary to uncover their properties when describing deformation, studying yield and failure, and developing test apparatus or equipment. The difficulties encountered in the above work would be greatly simplified if strain states could be expressed in a single strain form, namely including only linear or shear strains. As a start, this paper explores the meaning and nature of strain states. Then, based on the hypothesis of small deformations, two strain state expressions, the linear strain expression method (LSEM) and shear strain expression method (SSEM), were established for incompressible materials with only linear strain and shear strain as parameters respectively. Furthermore, conditions, implementation steps and specific forms for the application of SSEM in 1D, 2D and 3D strain states are obtained. As an example, two representations based on tetragonal pyramid and rotating tetrahedron are especially given. Therefore, conventional strain representation methods can be expressed as a combination of line strains in a certain direction or a combination of characteristic shear strains. The results of this paper provide a new way for understanding deformation characteristics, revealing yielding process, establishing constitutive models, and developing testing apparatus or equipment.

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Constitutive Model for Concrete: An Overview

Current World Environment ◽

10.12944/cwe.10.special-issue1.94 ◽

2015 ◽

Vol 10 (Special-Issue1) ◽

pp. 782-788 ◽

Cited By ~ 2

Author(s):

Mehdi Shekarbeigi ◽

Hasan Sharafi

Keyword(s):

Constitutive Model ◽

Damage Mechanics ◽

Constitutive Models ◽

Continuum Damage Mechanics ◽

Constitutive Modelling ◽

Continuum Damage ◽

Endochronic Theory ◽

Small Deformations

In the last three decades, the constitutive modelling of concrete evolved considerably. This paper describes various developments in this field based on different approaches such anelasticity, plasticity, continuum damage mechanics, plastic fracturing, endochronic theory, microplane models, etc. In this article the material is assumed to undergo small deformations. Only time independent constitutive models and the issues related to their implementation are discussed

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Early Manifestations of Short-Term Precursors in Stress-Strain State Dynamics of Southern California

Izvestiya Physics of the Solid Earth ◽

10.1134/s1069351321040042 ◽

2021 ◽

Vol 57 (4) ◽

pp. 508-519

Author(s):

V. G. Bondur ◽

M. B. Gokhberg ◽

I. A. Garagash ◽

D. A. Alekseev

Keyword(s):

Strain State ◽

Southern California ◽

Surrounding Medium ◽

Maximum Amplitude ◽

Theoretical Models ◽

Time Intervals ◽

Stress Strain ◽

Epicentral Zone ◽

Stress Strain State ◽

Shear Strains

Abstract—The stress-strain state before the М = 7.1 Ridgecrest earthquake in Southern California is analyzed based on spatiotemporal distribution of shear strains calculated in the geomechanical model within local ~100 × 100 km crustal segments at a depth of 3–7 km. In the epicentral zone of the earthquake, starting from three years before the event, a successive series of the time intervals, up to the occurrence of the earthquake, when shear deformations are completely absent and rocks are farthest from ultimate strength—the so-called quiescence zones—are established. The spatial distribution of shear strains in the vicinity of the epicentral zone is analyzed during the quiescence intervals and subsequent bursts of maximum amplitude in the epicentral zone itself. The time intervals of the bursts are called excursions. The successive emergence of maxima in shear strain amplitudes in the epicentral zone and surrounding medium during the excursions corresponds to the situation of a swing when the entire preparation region of a future earthquake is rocking up to the moment of event. Consistency of the obtained results with the existing theoretical models of earthquake preparation is discussed.

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Aquatic Toxic Analysis by Monitoring Fish Behavior Using Computer Vision: A Recent Progress

Journal of Toxicology ◽

10.1155/2018/2591924 ◽

2018 ◽

Vol 2018 ◽

pp. 1-11 ◽

Cited By ~ 7

Author(s):

Chunlei Xia ◽

Longwen Fu ◽

Zuoyi Liu ◽

Hui Liu ◽

Lingxin Chen ◽

...

Keyword(s):

Machine Learning ◽

Computer Vision ◽

Aquatic Toxicity ◽

Warning System ◽

Video Tracking ◽

Behavioral Data ◽

3D Space ◽

Biological Early Warning System ◽

Abnormal Pattern ◽

2D And 3D

Video tracking based biological early warning system achieved a great progress with advanced computer vision and machine learning methods. Ability of video tracking of multiple biological organisms has been largely improved in recent years. Video based behavioral monitoring has become a common tool for acquiring quantified behavioral data for aquatic risk assessment. Investigation of behavioral responses under chemical and environmental stress has been boosted by rapidly developed machine learning and artificial intelligence. In this paper, we introduce the fundamental of video tracking and present the pioneer works in precise tracking of a group of individuals in 2D and 3D space. Technical and practical issues suffered in video tracking are explained. Subsequently, the toxic analysis based on fish behavioral data is summarized. Frequently used computational methods and machine learning are explained with their applications in aquatic toxicity detection and abnormal pattern analysis. Finally, advantages of recent developed deep learning approach in toxic prediction are presented.

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Gold Exploration in Two and Three Dimensions: Improved and Correlative Insights from Microscopy and X-Ray Computed Tomography

Minerals ◽

10.3390/min10050476 ◽

2020 ◽

Vol 10 (5) ◽

pp. 476

Author(s):

Joshua Chisambi ◽

Bjorn von der Heyden ◽

Muofhe Tshibalanganda ◽

Stephan Le Roux

Keyword(s):

Computed Tomography ◽

Spatial Distribution ◽

Gold Mineralization ◽

Three Dimensional ◽

Three Dimensions ◽

Low Grade ◽

X Ray ◽

3D Space ◽

X Ray Computed ◽

2D And 3D

In this contribution, we highlight a correlative approach in which three-dimensional structural/positional data are combined with two dimensional chemical and mineralogical data to understand a complex orogenic gold mineralization system; we use the Kirk Range (southern Malawi) as a case study. Three dimensional structures and semi-quantitative mineral distributions were evaluated using X-ray Computed Tomography (XCT) and this was augmented with textural, mineralogical and chemical imaging using Scanning Electron Microscopy (SEM) and optical microscopy as well as fire assay. Our results detail the utility of the correlative approach both for quantifying gold concentrations in core samples (which is often nuggety and may thus be misrepresented by quarter- or half-core assays), and for understanding the spatial distribution of gold and associated structures and microstructures in 3D space. This approach overlays complementary datasets from 2D and 3D analytical protocols, thereby allowing a better and more comprehensive understanding on the distribution and structures controlling gold mineralization. Combining 3D XCT analyses with conventional 2D microscopies derive the full value out of a given exploration drilling program and it provides an excellent tool for understanding gold mineralization. Understanding the spatial distribution of gold and associated structures and microstructures in 3D space holds vast potential for exploration practitioners, especially if the correlative approach can be automated and if the resultant spatially-constrained microstructural information can be fed directly into commercially available geological modelling software. The extra layers of information provided by using correlative 2D and 3D microscopies offer an exciting new tool to enhance and optimize mineral exploration workflows, given that modern exploration efforts are targeting increasingly complex and low-grade ore deposits.

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AE-GAN-Net: Learning Invariant Feature Descriptor to Match Ground Camera Images and a Large-Scale 3D Image-Based Point Cloud for Outdoor Augmented Reality

Remote Sensing ◽

10.3390/rs11192243 ◽

2019 ◽

Vol 11 (19) ◽

pp. 2243 ◽

Cited By ~ 1

Author(s):

Weiquan Liu ◽

Cheng Wang ◽

Xuesheng Bian ◽

Shuting Chen ◽

Wei Li ◽

...

Keyword(s):

Image Matching ◽

Point Cloud ◽

Spatial Relationship ◽

3D Image ◽

Image Patch ◽

3D Space ◽

Cross Domain ◽

Feature Descriptors ◽

Outdoor Environments ◽

2D And 3D

Establishing the spatial relationship between 2D images captured by real cameras and 3D models of the environment (2D and 3D space) is one way to achieve the virtual–real registration for Augmented Reality (AR) in outdoor environments. In this paper, we propose to match the 2D images captured by real cameras and the rendered images from the 3D image-based point cloud to indirectly establish the spatial relationship between 2D and 3D space. We call these two kinds of images as cross-domain images, because their imaging mechanisms and nature are quite different. However, unlike real camera images, the rendered images from the 3D image-based point cloud are inevitably contaminated with image distortion, blurred resolution, and obstructions, which makes image matching with the handcrafted descriptors or existing feature learning neural networks very challenging. Thus, we first propose a novel end-to-end network, AE-GAN-Net, consisting of two AutoEncoders (AEs) with Generative Adversarial Network (GAN) embedding, to learn invariant feature descriptors for cross-domain image matching. Second, a domain-consistent loss function, which balances image content and consistency of feature descriptors for cross-domain image pairs, is introduced to optimize AE-GAN-Net. AE-GAN-Net effectively captures domain-specific information, which is embedded into the learned feature descriptors, thus making the learned feature descriptors robust against image distortion, variations in viewpoints, spatial resolutions, rotation, and scaling. Experimental results show that AE-GAN-Net achieves state-of-the-art performance for image patch retrieval with the cross-domain image patch dataset, which is built from real camera images and the rendered images from 3D image-based point cloud. Finally, by evaluating virtual–real registration for AR on a campus by using the cross-domain image matching results, we demonstrate the feasibility of applying the proposed virtual–real registration to AR in outdoor environments.

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Path Point Calculation and 3D Coordinate Display for WMR Based on Vision

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.121-126.4176 ◽

2011 ◽

Vol 121-126 ◽

pp. 4176-4179

Author(s):

Hong Wei Gao ◽

Chang Yi Luan ◽

Hui Ying Yang

Keyword(s):

Mobile Robot ◽

Wheeled Mobile Robot ◽

Simulation Platform ◽

Motion Simulation ◽

3D Space ◽

Point Calculation ◽

Simulation Results ◽

2D And 3D ◽

Path Point

According to the path point calculation, display and motion simulaiton problem for wheeled mobile robot(WMR), two kinds of path point calcualtion method are discussed from 2D and 3D space in this paper. The simulation results based on the motion simulation platform prove the validity and practicability of the proposed method.

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A Parametric Study on Interlaminar Shear Strains in Cord-Rubber Composites

Rubber Chemistry and Technology ◽

10.5254/1.3535992 ◽

1984 ◽

Vol 57 (1) ◽

pp. 168-183 ◽

Cited By ~ 4

Author(s):

J. DeEskinazi ◽

R. J. Cembrola

Keyword(s):

Shear Strain ◽

Relative Motion ◽

Strong Influence ◽

Design Parameters ◽

Cross Sectional ◽

Design Variables ◽

Study Results ◽

Shear Strains ◽

Interlaminar Shear ◽

Belt Width

Abstract The effect of different design variables used in the construction of tire belts on the interply shear phenomenon was studied using a simple, belted cylinder structure. Only balanced belt constructions were considered. The finite element method was used in the analysis of the belted structure. Predicted results were verified by performing experiments with selected combinations of the design parameters studied. Predicted and experimental results indicate the presence of interply shear strains in the cross-sectional plane of the belts; however, due to difficulties involved in measuring these strains experimentally, they have not been treated in this study. Results for shear strains in the circumferential planes only have been presented. Results for the interply shear strains at the belt edge indicate that the belt cord angle has a very strong influence on the interply shear phenomenon. It was shown that the shape of the curve depicting the relationship between cord angle and interply shear strains is influenced by other design variables of the belt as well as properties of adjacent plies, such as the bladder used to simulate a radial tire carcass ply. Interply shear strains decrease with increasing thickness between the plies and modulus of the interply rubber. In the case of a stiffer rubber, the reduction in shear strain is entirely due to a reduction in the relative motion between the belts. However, in the case of an increased interply thickness, which is accompanied by an increase in relative motion between the belts, the reduction in shear is the result of the relative motion being distributed over a larger thickness. Increasing the belt cord modulus results in an increase in interply shear strains for relatively low values of the modulus. However, beyond a certain value, approximately the modulus of fiberglass cords, increasing the cord modulus does not significantly affect interply shear strains. The shear strain-belt width relationship is strongly influenced by the cord angle used in the belts. Depending on the value of the latter, the shear strain can be a decreasing function of belt width or remain relatively constant as belt width is varied. The degree of localization of the interply shear phenomenon at the belt edge was also studied. All of the variables considered in this study, with the exception of the cord modulus, seem to affect the distribution of the shear strain along the width of the belt to varying extents. The belt width seems to have a strong influence, with wider belts resulting in significant shear strains confined to the vicinity of the belt edge.

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Formulation of the problem of finite deformations of a semi-toroidal shell under the internal pressure

Вестник Чувашского государственного педагогического университета им. И.Я. Яковлева. Серия: Механика предельного состояния ◽

10.37972/chgpu.2020.46.4.013 ◽

2020 ◽

pp. 155-163

Author(s):

Виктор Вячеславович Козлов ◽

Алексей Александрович Маркин ◽

Вера Евгеньевна Петрова

Keyword(s):

Internal Pressure ◽

Strain State ◽

Incompressible Material ◽

Toroidal Shell ◽

Nonlinear Ordinary Differential Equations ◽

The Finite Element Method ◽

Stress Strain ◽

Stress Strain State ◽

Nonlinear Elastic ◽

Small Deformations

Рассматривается нелинейно-упругая осесимметричная модель полутороидальной оболочки, закрепленной по основаниям, под действием внутреннего давления. Предложен подход к формулировке мер, определяющих напряженно-деформированное состояния оболочки. Для несжимаемого материала получена замкнутая система нелинейных обыкновенных дифференциальных уравнений относительно неизвестных функций. С помощью метода конечных элементов дана оценка напряженно-деформированного состояния оболочки в случае малых деформаций. A nonlinear elastic axisymmetric model of a semi-toroidal shell fixed at the bases under the internal pressure is considered. An approach to the formulation of measures that determine the stress-strain state of the shell is proposed. For an incompressible material, a closed system of nonlinear ordinary differential equations for unknown functions is obtained. The finite element method is used to estimate the stress-strain state of the shell in the case of small deformations.

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