The Experts below are selected from a list of 231 Experts worldwide ranked by ideXlab platform

A. H. Yaghi - One of the best experts on this subject based on the ideXlab platform.

  • Residual stress simulation in thin and thick-walled stainless steel pipe welds including pipe diameter effects
    International Journal of Pressure Vessels and Piping, 2006
    Co-Authors: A. H. Yaghi, A. A. Becker, Thomas H. Hyde, J A Williams
    Abstract:

    Abstract In this paper, residual stresses in welded components are discussed and a brief review of weld simulation is presented. The general methodology of the FE analysis methods used for welded sections of steel pipes is explained. FE analyses are performed for two axisymmetric butt welds in stainless steel pipes having a 4-pass or a 36-pass weld in a pipe with a wall thickness of 7.1 or 40.0 mm, respectively. In addition, more FE models with Inside Radius to wall thickness ratio ranging from 1 to 100 have been analysed to investigate the effect of pipe diameter on residual stresses. Residual axial and hoop stresses are plotted for the considered range of pipe diameters for the two simulated pipe wall thicknesses and the differences are discussed.

  • Residual stress simulation in welded sections of P91 pipes
    Journal of Materials Processing Technology, 2005
    Co-Authors: A. H. Yaghi, A. A. Becker, J A Williams, Thomas H. Hyde, W. Sun
    Abstract:

    In this paper, a brief review of weld simulation and residual stress modelling using the finite element (FE) method is presented. The method of FE analysis of welded sections of P91 pipes is described. Mechanical and thermal material properties used in the modelling are related to a general P91 parent steel database, generated from available literature. Two specific FE examples are described, which are axisymmetric butt welds in P91 steel pipes having a 4 or 36 pass weld in a pipe with wall thickness of 7.1 or 40.0 mm, respectively. As part of a parametric study, eight more FE models with Inside Radius to wall thickness ratio ranging from 1 to 100 have been analysed to investigate the effect of pipe diameter on residual stresses. The thermal analysis has revealed temperature contours, which indicate the size of the weld region and the heat affected zone (HAZ). Residual axial and hoop stresses obtained from the analysis have been shown for a range of pipe diameters for the two pipe wall thicknesses. Trends of behaviour of residual stresses have emerged for the set of material properties implemented in the FE analysis. In addition, the effect of pipe diameter on the residual stresses has been presented. © 2005 Elsevier B.V. All rights reserved.

W. Sun - One of the best experts on this subject based on the ideXlab platform.

  • Residual stress simulation in welded sections of P91 pipes
    Journal of Materials Processing Technology, 2005
    Co-Authors: A. H. Yaghi, A. A. Becker, J A Williams, Thomas H. Hyde, W. Sun
    Abstract:

    In this paper, a brief review of weld simulation and residual stress modelling using the finite element (FE) method is presented. The method of FE analysis of welded sections of P91 pipes is described. Mechanical and thermal material properties used in the modelling are related to a general P91 parent steel database, generated from available literature. Two specific FE examples are described, which are axisymmetric butt welds in P91 steel pipes having a 4 or 36 pass weld in a pipe with wall thickness of 7.1 or 40.0 mm, respectively. As part of a parametric study, eight more FE models with Inside Radius to wall thickness ratio ranging from 1 to 100 have been analysed to investigate the effect of pipe diameter on residual stresses. The thermal analysis has revealed temperature contours, which indicate the size of the weld region and the heat affected zone (HAZ). Residual axial and hoop stresses obtained from the analysis have been shown for a range of pipe diameters for the two pipe wall thicknesses. Trends of behaviour of residual stresses have emerged for the set of material properties implemented in the FE analysis. In addition, the effect of pipe diameter on the residual stresses has been presented. © 2005 Elsevier B.V. All rights reserved.

Kyongho Chang - One of the best experts on this subject based on the ideXlab platform.

  • three dimensional finite element simulation of residual stresses in circumferential welds of steel pipe including pipe diameter effects
    Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2008
    Co-Authors: Kyongho Chang
    Abstract:

    In circumferential welding of a pipe component, it is often considered that axisymmetric model can provide a reasonable prediction of the residual stress distributions. However, in general, the axisymmetric model cannot reproduce the traveling arc along circumferential welds and rapid change of residual stresses that can be observed in the overlapping region. Moreover, it tends to overestimate the hoop residual stresses in circumferential welds. Therefore, three-dimensional finite element (FE) model is essential for the accurate simulation of circumferential welding which can incorporate the three-dimensional effects. This paper presents the three-dimensional FE simulation of circumferential butt welding of a steel pipe. The thermo-mechanical model used as well as the simulation methodology is detailed, and the results are discussed. In addition, parametric studies with Inside Radius to wall thickness ratio ranging from 10.0 to 100.0 have been presented to investigate the effects of pipe diameter on residual stresses. Axial and hoop residual stresses are plotted for the considered range of pipe diameters, and the differences are discussed.

J A Williams - One of the best experts on this subject based on the ideXlab platform.

  • Residual stress simulation in thin and thick-walled stainless steel pipe welds including pipe diameter effects
    International Journal of Pressure Vessels and Piping, 2006
    Co-Authors: A. H. Yaghi, A. A. Becker, Thomas H. Hyde, J A Williams
    Abstract:

    Abstract In this paper, residual stresses in welded components are discussed and a brief review of weld simulation is presented. The general methodology of the FE analysis methods used for welded sections of steel pipes is explained. FE analyses are performed for two axisymmetric butt welds in stainless steel pipes having a 4-pass or a 36-pass weld in a pipe with a wall thickness of 7.1 or 40.0 mm, respectively. In addition, more FE models with Inside Radius to wall thickness ratio ranging from 1 to 100 have been analysed to investigate the effect of pipe diameter on residual stresses. Residual axial and hoop stresses are plotted for the considered range of pipe diameters for the two simulated pipe wall thicknesses and the differences are discussed.

  • Residual stress simulation in welded sections of P91 pipes
    Journal of Materials Processing Technology, 2005
    Co-Authors: A. H. Yaghi, A. A. Becker, J A Williams, Thomas H. Hyde, W. Sun
    Abstract:

    In this paper, a brief review of weld simulation and residual stress modelling using the finite element (FE) method is presented. The method of FE analysis of welded sections of P91 pipes is described. Mechanical and thermal material properties used in the modelling are related to a general P91 parent steel database, generated from available literature. Two specific FE examples are described, which are axisymmetric butt welds in P91 steel pipes having a 4 or 36 pass weld in a pipe with wall thickness of 7.1 or 40.0 mm, respectively. As part of a parametric study, eight more FE models with Inside Radius to wall thickness ratio ranging from 1 to 100 have been analysed to investigate the effect of pipe diameter on residual stresses. The thermal analysis has revealed temperature contours, which indicate the size of the weld region and the heat affected zone (HAZ). Residual axial and hoop stresses obtained from the analysis have been shown for a range of pipe diameters for the two pipe wall thicknesses. Trends of behaviour of residual stresses have emerged for the set of material properties implemented in the FE analysis. In addition, the effect of pipe diameter on the residual stresses has been presented. © 2005 Elsevier B.V. All rights reserved.

C.r. Martin - One of the best experts on this subject based on the ideXlab platform.

  • Metal Nanotubule Membranes with Electrochemically Switchable Ion-Transport Selectivity
    Science, 1995
    Co-Authors: Matsuhiko Nishizawa, V. P. Menon, C.r. Martin
    Abstract:

    Membranes containing cylindrical metal nanotubules that span the complete thickness of the membrane are described. The Inside Radius of the nanotubules can be varied at will; nanotubule radii as small as 0.8 nanometer are reported. These membranes show selective ion transport analogous to that observed in ion-exchange polymers. Ion permselectivity occurs because excess charge density can be present on the inner walls of the metal tubules. The membranes reject ions with the same sign as the excess charge and transport ions of the opposite sign. Because the sign of the excess charge on the tubule can be changed potentiostatically, a metal nanotubule membrane can be either cation selective or anion selective, depending on the potential applied to the membrane.

  • Metal Nanotubule Membranes with Electrochemically Switchable Ion-Transport Selectivity
    Science, 1995
    Co-Authors: Matsuhiko Nishizawa, V. P. Menon, C.r. Martin
    Abstract:

    Accessed: 01-12-2016 18:37 UTC JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org. Membranes containing cylindrical metal nanotubules that span the complete thickness of the membrane are described. The Inside Radius of the nanotubules can be varied at will; nanotubule radii as small as 0.8 nanometer are reported. These membranes show se-lective ion transport analogous to that observed in ion-exchange polymers. Ion perm-selectivity occurs because excess charge density can be present on the inner walls of the metal tubules. The membranes reject ions with the same sign as the excess charge and transport ions of the opposite sign. Because the sign of the excess charge on the tubule can be changed potentiostatically, a metal nanotubule membrane can be either cation selective or anion selective, depending on the potential applied to the membrane. A variety of materials that contain pores of molecular dimensions are known, including the porin proteins (1, 2), zeolites (3), and fullerene tubules (4). Synthetic membranes with monodisperse pores that approach mo-lecular dimensions might be useful as mim-ics for biological systems and would be use-ful in membrane science and technology. Here we introduce a class of membranes that contain cylindrical nanoscopic metal tubules that run the complete width of the membrane. These metal nanotubule mem-branes show selective ion transport analo-gous to that observed in ion-exchange poly-mers (5). Ion permselectivity (6) occurs because excess charge density can be present on the inner walls of the tubules. The tubes reject ions of the same sign, and transport ions of the opposite sign, as this excess charge. This is only possible when the Inside Radius of the tubule is small rel-ative to the thickness of the electrical dou-ble layer (7) within the tubule. These mem-branes can be either cation-selective or an-ion-selective, depending on the potential applied to the membrane; hence, these met-al nanotubule membranes can be viewed as universal ion exchange membranes. The pores in a commercially available polycarbonate filtration membrane (Poret-ics) were used as templates (8) to form the metal (Au) nanotubules. These membranes contain cylindrical nanopores of uniform