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Liqun Li - One of the best experts on this subject based on the ideXlab platform.

  • prediction of laser welding induced deformation in thin sheets by efficient numerical modeling
    Journal of Materials Processing Technology, 2016
    Co-Authors: Hui Huang, Jiandong Wang, Liqun Li
    Abstract:

    Abstract A local solid model and a global shell model were employed for fast prediction of deformation in laser welded thin sheets based on inherent strain theory. Transient thermo-Elastic-Plastic Analysis was performed on the local three-dimensional solid model to obtain inherent strain for the global shell model. To ensure solution accuracy, the characteristics of the laser welding heat source were considered in determination of the mesh size and time increment. The penetration shape of laser welded joint was well reproduced compared with the results by experimental observation. By applying inherent strain into shell element model, the out-of-plane welding deformation was predicted within a few minutes using elastic FEM. The predicted deformation mode and magnitude agreed with the measured ones for laser welded joints of different dimensions. By considering geometrical imperfection in the numerical model, it was reproduced that the laser welding induced deformation in thin sheets generally has the same mode as initial shape of the sheet.

  • prediction of laser welding induced deformation in thin sheets by efficient numerical modeling
    Journal of Materials Processing Technology, 2016
    Co-Authors: Hui Huang, Jiandong Wang, Liqun Li
    Abstract:

    Abstract A local solid model and a global shell model were employed for fast prediction of deformation in laser welded thin sheets based on inherent strain theory. Transient thermo-Elastic-Plastic Analysis was performed on the local three-dimensional solid model to obtain inherent strain for the global shell model. To ensure solution accuracy, the characteristics of the laser welding heat source were considered in determination of the mesh size and time increment. The penetration shape of laser welded joint was well reproduced compared with the results by experimental observation. By applying inherent strain into shell element model, the out-of-plane welding deformation was predicted within a few minutes using elastic FEM. The predicted deformation mode and magnitude agreed with the measured ones for laser welded joints of different dimensions. By considering geometrical imperfection in the numerical model, it was reproduced that the laser welding induced deformation in thin sheets generally has the same mode as initial shape of the sheet.

Hui Huang - One of the best experts on this subject based on the ideXlab platform.

  • prediction of laser welding induced deformation in thin sheets by efficient numerical modeling
    Journal of Materials Processing Technology, 2016
    Co-Authors: Hui Huang, Jiandong Wang, Liqun Li
    Abstract:

    Abstract A local solid model and a global shell model were employed for fast prediction of deformation in laser welded thin sheets based on inherent strain theory. Transient thermo-Elastic-Plastic Analysis was performed on the local three-dimensional solid model to obtain inherent strain for the global shell model. To ensure solution accuracy, the characteristics of the laser welding heat source were considered in determination of the mesh size and time increment. The penetration shape of laser welded joint was well reproduced compared with the results by experimental observation. By applying inherent strain into shell element model, the out-of-plane welding deformation was predicted within a few minutes using elastic FEM. The predicted deformation mode and magnitude agreed with the measured ones for laser welded joints of different dimensions. By considering geometrical imperfection in the numerical model, it was reproduced that the laser welding induced deformation in thin sheets generally has the same mode as initial shape of the sheet.

  • prediction of laser welding induced deformation in thin sheets by efficient numerical modeling
    Journal of Materials Processing Technology, 2016
    Co-Authors: Hui Huang, Jiandong Wang, Liqun Li
    Abstract:

    Abstract A local solid model and a global shell model were employed for fast prediction of deformation in laser welded thin sheets based on inherent strain theory. Transient thermo-Elastic-Plastic Analysis was performed on the local three-dimensional solid model to obtain inherent strain for the global shell model. To ensure solution accuracy, the characteristics of the laser welding heat source were considered in determination of the mesh size and time increment. The penetration shape of laser welded joint was well reproduced compared with the results by experimental observation. By applying inherent strain into shell element model, the out-of-plane welding deformation was predicted within a few minutes using elastic FEM. The predicted deformation mode and magnitude agreed with the measured ones for laser welded joints of different dimensions. By considering geometrical imperfection in the numerical model, it was reproduced that the laser welding induced deformation in thin sheets generally has the same mode as initial shape of the sheet.

Masahito Mochizuki - One of the best experts on this subject based on the ideXlab platform.

  • welding metallurgical evaluation for residual stress measurement accuracy of multi pass girth welded pipe joint in austenitic stainless steel by x ray diffraction
    Journal of The Society of Materials Science Japan, 2011
    Co-Authors: Tadafumi Hashimoto, Shigetaka Okano, Masahito Mochizuki
    Abstract:

    In welded pipe joints of austenitic stainless steel, the mismatch of residual stress distribution often occurs between a variety of measurement method and the numerical simulation. It is especially known that non-destructive measurement such as X-ray diffraction method makes remarkable different due to the microstructure evolution by the welding. Meanwhile, the multi-pass girth welded pipe joints of austenitic stainless steel in this work were consistent with the thermal-Elastic-Plastic Analysis and the typical stress distribution due to the welding was obtained. This reason was clarified from the welding metallurgical evaluation. The material of FA (ferrite to austenite) mode solidification with K-S relationship has the random and fine structure, compared with other systems. Therefore, specific systems facilitate the X-ray stress measurement in the welded zone of austenitic stainless steel and the pure stress by the welding could evaluate.

  • evaluation of through thickness residual stress in multipass butt welded joint by using inherent strain
    Science and Technology of Welding and Joining, 2006
    Co-Authors: Masahito Mochizuki
    Abstract:

    The through thickness residual stress of an eight pass butt welded plate joint is evaluated using inherent strain Analysis. The residual stress distribution is obtained in detail along the thickness direction from measurements using multiple strain gauges. The residual stresses agree with the results of the thermal elastic–plastic Analysis as well as the values obtained by direct measurement of the specimen surface, which is not used in inherent strain Analysis. These results indicate that both inherent strain Analysis and thermal elastic–plastic Analysis are effective in evaluating through thickness residual stress. Therefore, each Analysis method should be chosen after considering the object to be evaluated and the characteristics to be analysed.

  • Effect of Plastic Constraint and Strain Rate on Characteristics of Strength and Fracture in Undermatched Joints
    Computational Weld Mechanics Constraint and Weld Fracture, 2002
    Co-Authors: Masahito Mochizuki, Masao Toyoda
    Abstract:

    Welded joint generally has heterogeneity of strength, material, and fracture toughness. It is important to understand the characteristics of material strength and fracture in welded joint considering plastic constraint effect due to material heterogeneity. Furthermore, the material behavior becomes more complicated when welded joint receives dynamic loading like as earthquake. In this paper, the characteristics of strength and fracture in undermatched joints with strength heterogeneity under dynamic loading were studied by round-bar tension tests and thermal Elastic-Plastic Analysis. These strength and fracture in undermatched joints are evaluated by considering the effects of strain rate and temperature including temperature rise due to rapid plastic deformation. The differences of fracture characteristics such as ductile-to-brittle transition behavior are considered from the plastic constraint effect and strain rate effect, and they are precisely explained in terms of the stress-strain distribution obtained by numerical Analysis.Copyright © 2002 by ASME

  • residual stress distribution depending on welding sequence in multi pass welded joints with x shaped groove
    Journal of Pressure Vessel Technology-transactions of The Asme, 2000
    Co-Authors: Masahito Mochizuki, Makoto Hayashi, Toshio Hattori
    Abstract:

    Residual stress in a large-diameter multi-pass butt-welded pipe joint was calculated for various welding pass sequences by thermal Elastic-Plastic Analysis using the finite element method. The pipe joint used had an X-shaped groove, and the sequences of welding passes were changed. The distribution of residual stress depends on the welding pass sequences. The mechanism that produces residual stress in the welded pipe joint was studied in detail by using a simple prediction model. An optimum welding sequence for preventing stress-corrosion cracking was determined from the residual stress distribution.

  • numerical Analysis of welding residual stress and its verification using neutron diffraction measurement
    Journal of Engineering Materials and Technology-transactions of The Asme, 2000
    Co-Authors: Masahito Mochizuki, Makoto Hayashi, Toshio Hattori
    Abstract:

    Direct measurements and computed distributions of through-thickness residual stress in a pipe butt-welded joint and a pipe socket-welded joint are compared. The analytical evaluation methods used were inherent strain Analysis and thermal Elastic-Plastic Analysis. The experimental methods were neutron diffraction for the internal residual stress, and X-ray diffraction and strain-gauge measurement for the surface stress. The residual stress distributions determined using these methods agreed well with each other, both for internal stress and surface stress. The characteristics of the evaluation methods and the suitability of these methods for each particular welded object to be evaluated are discussed.

Jiandong Wang - One of the best experts on this subject based on the ideXlab platform.

  • prediction of laser welding induced deformation in thin sheets by efficient numerical modeling
    Journal of Materials Processing Technology, 2016
    Co-Authors: Hui Huang, Jiandong Wang, Liqun Li
    Abstract:

    Abstract A local solid model and a global shell model were employed for fast prediction of deformation in laser welded thin sheets based on inherent strain theory. Transient thermo-Elastic-Plastic Analysis was performed on the local three-dimensional solid model to obtain inherent strain for the global shell model. To ensure solution accuracy, the characteristics of the laser welding heat source were considered in determination of the mesh size and time increment. The penetration shape of laser welded joint was well reproduced compared with the results by experimental observation. By applying inherent strain into shell element model, the out-of-plane welding deformation was predicted within a few minutes using elastic FEM. The predicted deformation mode and magnitude agreed with the measured ones for laser welded joints of different dimensions. By considering geometrical imperfection in the numerical model, it was reproduced that the laser welding induced deformation in thin sheets generally has the same mode as initial shape of the sheet.

  • prediction of laser welding induced deformation in thin sheets by efficient numerical modeling
    Journal of Materials Processing Technology, 2016
    Co-Authors: Hui Huang, Jiandong Wang, Liqun Li
    Abstract:

    Abstract A local solid model and a global shell model were employed for fast prediction of deformation in laser welded thin sheets based on inherent strain theory. Transient thermo-Elastic-Plastic Analysis was performed on the local three-dimensional solid model to obtain inherent strain for the global shell model. To ensure solution accuracy, the characteristics of the laser welding heat source were considered in determination of the mesh size and time increment. The penetration shape of laser welded joint was well reproduced compared with the results by experimental observation. By applying inherent strain into shell element model, the out-of-plane welding deformation was predicted within a few minutes using elastic FEM. The predicted deformation mode and magnitude agreed with the measured ones for laser welded joints of different dimensions. By considering geometrical imperfection in the numerical model, it was reproduced that the laser welding induced deformation in thin sheets generally has the same mode as initial shape of the sheet.

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

  • elastic and elastic plastic Analysis of multilayer thin films closed form solutions
    Journal of Applied Physics, 2004
    Co-Authors: Y Y Hu, W M Huang
    Abstract:

    The stress and curvature induced by temperature fluctuation in multilayer thin film structures have been investigated extensively in the past. However, most of the previous efforts were focused on the elastic deformation range. In this paper, first we propose a simple approach to derive the closed-form solutions in multilayer thin film structures in the elastic range. Subsequently, approximate solutions are obtained for very thin multilayer films. The condition that the film stress is of the same sign is identified for bilayer cases. The investigation is then extended into the Elastic-Plastic deformed films in bilayer structures. Closed-form solutions of the maximum, average, and minimum film stresses and curvatures are obtained for plastically deformed films. It is concluded that for an error within ±10% as compared with that of Stoney equation, it is required that the thickness ratio should be about 0.1 or less for whatever elastic or Elastic-Plastic Analysis. In addition, the result of a case study rev...