Deformation mechanism of copper reinforced by three-dimensional graphene under torsion and tension

Abstract The mechanical behaviors of uniaxial torsional and tensional copper nanorod embedded with sp2-type hybrid graphene nanosheets (3DG/Cu) were investigated systematically using molecular dynamics methods. During the torsion process, graphene expanded the plastic deformation region of copper, while the plastic deformation in monocrystalline Cu cases was limited to a smaller area. 3DG/Cu responded to the torsion by one more plastic stage when plastic deformation spread along the length after the elastic response. Graphene improved the torsional loading capacity of the composite material, greatly extending the effective response range of the material by distributing the deformation of copper along with the graphene rather than being concentrated at a certain position like monocrystalline Cu. Generally, as the length of the model increased, this enhancement decreased. The copper portion of 3DG/Cu was divided into three areas during uniaxial tensile, a static region, a quasi-static region of the middle portion where the shear and necking occurred, and a dynamic area near the loading end. However, the inside graphene kept continuous until fracture. Furthermore, graphene improved the yield strain of copper by maintaining intact after copper failure. The greater the pre-loaded torsion angle, the smaller the yield strength and Young's modulus of 3DG/Cu.

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Construction of plastic contact deformation maps on ceramics: a case study on aluminum nitride

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100165641 ◽

1996 ◽

Vol 54 ◽

pp. 636-637

Author(s):

D. L. Callahan

Keyword(s):

Plastic Deformation ◽

Aluminum Nitride ◽

Mechanical Response ◽

Three Dimensional ◽

Bright Field Image ◽

Perfectly Plastic ◽

Contrast Analysis ◽

Deformation Patterns

Modern polishing, precision machining and microindentation techniques allow the processing and mechanical characterization of ceramics at nanometric scales and within entirely plastic deformation regimes. The mechanical response of most ceramics to such highly constrained contact is not predictable from macroscopic properties and the microstructural deformation patterns have proven difficult to characterize by the application of any individual technique. In this study, TEM techniques of contrast analysis and CBED are combined with stereographic analysis to construct a three-dimensional microstructure deformation map of the surface of a perfectly plastic microindentation on macroscopically brittle aluminum nitride.The bright field image in Figure 1 shows a lg Vickers microindentation contained within a single AlN grain far from any boundaries. High densities of dislocations are evident, particularly near facet edges but are not individually resolvable. The prominent bend contours also indicate the severity of plastic deformation. Figure 2 is a selected area diffraction pattern covering the entire indentation area.

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Three-dimensional microstructure and texture evolution of Ti35 alloy applied in nuclear industry during plastic deformation at various temperatures

Materials Science and Engineering A ◽

10.1016/j.msea.2021.141508 ◽

2021 ◽

pp. 141508

Author(s):

Jianping Xu ◽

Chengze Liu ◽

Jinping Wu ◽

Boyi Qi ◽

Yusheng Zhang ◽

...

Keyword(s):

Plastic Deformation ◽

Texture Evolution ◽

Three Dimensional ◽

Nuclear Industry

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Effect of Residual Stress or Plastic Deformation History on Fatigue Life Simulation of Pipeline Dents

Volume 1: Pipeline and Facilities Integrity ◽

10.1115/ipc2018-78805 ◽

2018 ◽

Author(s):

Xian-Kui Zhu ◽

Rick Wang

Keyword(s):

Residual Stress ◽

Plastic Deformation ◽

Fatigue Life ◽

Residual Stresses ◽

Three Dimensional ◽

Strain History ◽

Deformation History ◽

Stress Strain ◽

Element Analysis ◽

Fea Model

Mechanical dents often occur in transmission pipelines, and are recognized as one of major threats to pipeline integrity because of the potential fatigue failure due to cyclic pressures. With matured in-line-inspection (ILI) technology, mechanical dents can be identified from the ILI runs. Based on ILI measured dent profiles, finite element analysis (FEA) is commonly used to simulate stresses and strains in a dent, and to predict fatigue life of the dented pipeline. However, the dent profile defined by ILI data is a purely geometric shape without residual stresses nor plastic deformation history, and is different from its actual dent that contains residual stresses/strains due to dent creation and re-rounding. As a result, the FEA results of an ILI dent may not represent those of the actual dent, and may lead to inaccurate or incorrect results. To investigate the effect of residual stress or plastic deformation history on mechanics responses and fatigue life of an actual dent, three dent models are considered in this paper: (a) a true dent with residual stresses and dent formation history, (b) a purely geometric dent having the true dent profile with all stress/strain history removed from it, and (c) a purely geometric dent having an ILI defined dent profile with all stress/strain history removed from it. Using a three-dimensional FEA model, those three dents are simulated in the elastic-plastic conditions. The FEA results showed that the two geometric dents determine significantly different stresses and strains in comparison to those in the true dent, and overpredict the fatigue life or burst pressure of the true dent. On this basis, suggestions are made on how to use the ILI data to predict the dent fatigue life.

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Numerical Analysis of the Perforated Steel Sheets Under Uni-Axial Tensile Force

Metals ◽

10.3390/met9060632 ◽

2019 ◽

Vol 9 (6) ◽

pp. 632 ◽

Cited By ~ 1

Author(s):

Ahmed M. Sayed

Keyword(s):

Load Capacity ◽

Tensile Force ◽

Three Dimensional ◽

Tensile Load ◽

Experimental Tests ◽

Strain Engineering ◽

Uniaxial Tensile ◽

Fe Model ◽

Stress Strain ◽

Steel Sheets

The perforated steel sheets have many uses, so they should be studied under the influence of the uniaxial tensile load. The presence of these holes in the steel sheets certainly affects the mechanical properties. This paper aims at studying the behavior of the stress-strain engineering relationships of the perforated steel sheets. To achieve this, the three-dimensional finite element (FE) model is mainly designed to investigate the effect of this condition. Experimental tests were carried out on solid specimens to be used in the test of model accuracy of the FE simulation. Simulation testing shows that the FE modeling revealed the ability to calculate the stress-strain engineering relationships of perforated steel sheets. It can be concluded that the effect of a perforated rhombus shape is greater than the others, and perforated square shape has no effect on the stress-strain engineering relationships. The efficiency of the perforated staggered or linearly distribution shapes with the actual net area on the applied loads has the opposite effect, as it reduces the load capacity for all types of perforated shapes. Despite the decrease in load capacity, it improves the properties of the steel sheets.

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Effect of Uniaxial Tensile Cyclic Loading Regimes on Matrix Organization and Tenogenic Differentiation of Adipose-Derived Stem Cells Encapsulated within 3D Collagen Scaffolds

Stem Cells International ◽

10.1155/2017/6072406 ◽

2017 ◽

Vol 2017 ◽

pp. 1-16 ◽

Cited By ~ 5

Author(s):

Gayathri Subramanian ◽

Alexander Stasuk ◽

Mostafa Elsaadany ◽

Eda Yildirim-Ayan

Keyword(s):

Gene Expression ◽

Stem Cells ◽

Expression Profiles ◽

Three Dimensional ◽

Uniaxial Tensile ◽

Adipose Derived Stem Cells ◽

Collagen Scaffolds ◽

Differentiation Potential ◽

Tenogenic Differentiation ◽

Matrix Organization

Adipose-derived mesenchymal stem cells have become a popular cell choice for tendon repair strategies due to their relative abundance, ease of isolation, and ability to differentiate into tenocytes. In this study, we investigated the solo effect of different uniaxial tensile strains and loading frequencies on the matrix directionality and tenogenic differentiation of adipose-derived stem cells encapsulated within three-dimensional collagen scaffolds. Samples loaded at 0%, 2%, 4%, and 6% strains and 0.1 Hz and 1 Hz frequencies for 2 hours/day over a 7-day period using a custom-built uniaxial tensile strain bioreactor were characterized in terms of matrix organization, cell viability, and musculoskeletal gene expression profiles. The results displayed that the collagen fibers of the loaded samples exhibited increased matrix directionality with an increase in strain values. Gene expression analyses demonstrated that ASC-encapsulated collagen scaffolds loaded at 2% strain and 0.1 Hz frequency showed significant increases in extracellular matrix genes and tenogenic differentiation markers. Importantly, no cross-differentiation potential to osteogenic, chondrogenic, and myogenic lineages was observed at 2% strain and 0.1 Hz frequency loading condition. Thus, 2% strain and 0.1 Hz frequency were identified as the appropriate mechanical loading regime to induce tenogenic differentiation of adipose-derived stem cells cultured in a three-dimensional environment.

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Microstructure evolution and plastic deformation of Ni47Co53 alloy under tension

CrystEngComm ◽

10.1039/d1ce01446c ◽

2022 ◽

Author(s):

ruibo ma ◽

Lili Zhou ◽

Yong-Chao Liang ◽

Ze-an Tian ◽

Yun-Fei Mo ◽

...

Keyword(s):

Molecular Dynamics ◽

Plastic Deformation ◽

Rapid Solidification ◽

Microstructural Evolution ◽

Microstructure Evolution ◽

Cooling Rates ◽

Solidification Processes ◽

Molecular Dynamics Methods

To investigate microstructural evolution and plastic deformation under tension conditions, the rapid solidification processes of Ni47Co53 alloy are first simulated by molecular dynamics methods at cooling rates of 1011, 1012...

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Elasto-plastic analysis of the contact region between a rigid ellipsoid and a semi-flat surface

Advances in Mechanical Engineering ◽

10.1177/1687814018797397 ◽

2018 ◽

Vol 10 (9) ◽

pp. 168781401879739 ◽

Cited By ~ 1

Author(s):

Pengyang Li ◽

Lingxia Zhou ◽

Fangyuan Cui ◽

Quandai Wang ◽

Meiling Guo ◽

...

Keyword(s):

Residual Stress ◽

Plastic Deformation ◽

Plastic Strain ◽

Contact Pressure ◽

Contact Region ◽

Three Dimensional ◽

Von Mises Stress ◽

Effective Plastic Strain ◽

Normal Forces ◽

Von Mises

When the load acting on a mechanical structure is greater than the yield strength of the material, the contact surface will undergo plastic deformation. Cumulative plastic deformation has an important influence on the lifespan of mechanical parts. This article presents a three-dimensional semi-analytical model based on the conjugate gradient method and fast Fourier transform algorithm, with the aim of studying the characteristic parameters of the contact region between a rigid ellipsoid and elasto-plastic half-space. Moreover, normal forces and tangential traction were considered, as well as the contact pressure resulting from various sliding speeds and friction coefficients. The contact pressure, effective plastic strain, von Mises stress, and residual stress were measured and shown to increase with increasing sliding velocity. Finally, when the friction coefficient, contact pressure, and effective plastic strain are increased, the von Mises stress is also shown to increase, whereas the residual stress decreases.

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