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Hidekazu Murakawa - One of the best experts on this subject based on the ideXlab platform.

  • applications of inherent strain and Interface Element to simulation of welding deformation in thin plate structures
    Computational Materials Science, 2012
    Co-Authors: Hidekazu Murakawa, Dean Deng, Jiangchao Wang
    Abstract:

    Welding-induced distortion not only reduces largely manufacturing accuracy but also decreases significantly productivity due to correction works. If welding distortion can be predicted through a simple and practical method beforehand, the predictions will be helpful for taking active as well as appropriate measures to control the dimension accuracy. Based on inherent strain theory and Interface Element formulation, we developed a practical prediction system to compute the accumulated distortion during the welding assembly process in the current study. Using the developed prediction method, we calculated the welding distortion in a thin plate structure with considering both the shrinkage due to heat input and the gap/misalignment generated during assembly process. Meanwhile, we investigated the influences of assembly sequence and gap correction on the final distortion.

  • predicting welding deformation in thin plate panel structure by means of inherent strain and Interface Element
    Science and Technology of Welding and Joining, 2012
    Co-Authors: D Deng, Hidekazu Murakawa
    Abstract:

    In this study, welding distortion in a large thin plate panel structure was predicted by means of elastic finite Element method based on inherent strain theory and Interface Element formulation. The welding distortions in the thin plate model computed by large deformation theory and small deformation theory were compared. The comparison suggests that the geometrical non-linearity should be carefully considered when welding distortion in a thin plate structure is predicted. In addition, the influences of welding procedure and assembly sequence on the final distortion were examined numerically. Simulation results indicate that both welding procedure and assembly sequence significantly affect the final deformation.

  • Basic analysis of microstructural fracture behavior in structural materials by using FEM with Interface Element
    Procedia Engineering, 2011
    Co-Authors: Hajime Serizawa, Seigo Tomiyama, Tsuyoshi Hajima, Hidekazu Murakawa
    Abstract:

    Abstract A new finite Element method with the Interface Element was developed for examining the microstructural fracture behavior, where the anisotropy of grain was modeled by the ordinary finite Element while both the opening and shear deformations was demonstrated by the Interface Element. From the serial computations using two-dimensional virtual polycrystalline models obtained through Voronoi tessellations, it was found that the interaction between the interaction between opening and shear deformations would be a dominant factor of the fracture processes. Also, it can be concluded that this method would be a useful tool for examining microstructural fracture behavior. © 2011 Published by Elsevier Ltd. Selection and peer-review under responsibility of ICM11

  • Preliminary Numerical Research of Microstructural Fracture Behavior in Metal by Using Interface Element
    QUARTERLY JOURNAL OF THE JAPAN WELDING SOCIETY, 2011
    Co-Authors: Seigo Tomiyama, Hajime Serizawa, Tsuyoshi Hajima, Hidekazu Murakawa
    Abstract:

    In order to demonstrate not only the deformation of grain but also the opening and/or sliding at grain boundary, the Interface Element was introduced into the ordinary finite Element method, and this numerical method was applied for examining the microstructural fracture behavior in two-dimensional ideal microstructure obtained through Voronoi tessellations. As for the grain, the anisotropy in elastic modulus due to the grain orientation was taken into account, while the fracture strength at grain boundary was assumed to be related to the boundary energy which could be determined by the atomic disorder at the boundary. From the serial computational results for examining the influences of elastic properties in grain (isotropy and anisotropy), mechanical property at grain boundary (interaction between opening and sliding deformation), and grain configurations, it was revealed that all the factors varied in this research might affect the microstructural fracture behavior. Also, it can be concluded that this numerical method with the Interface Element can be useful for demonstrating the microstructural fracture behavior including the deformation at grain boundary.

  • prediction of distortion produced on welded structures during assembly using inherent deformation and Interface Element
    Transactions of JWRI, 2009
    Co-Authors: Hidekazu Murakawa, Dean Deng, Sherif Rashed, Shinji Sato
    Abstract:

    The objective of this research is to develop a practically useful finite Element method for predicting distortions of structures under welding assembly. In this method, distortions produced by various thermal processes, such as the cutting, the forming, the welding and the straightening can be considered. These distortions are simulated using the inherent strain. On the other hand, the detail of how the gaps and the misalignments are controlled during the fitting process also has significant influence on the distortion. The gaps and the misalignments between parts are modeled using the Interface Element. The potential capability of the proposed method is demonstrated through simple examples.

Manicka Dhanasekar - One of the best experts on this subject based on the ideXlab platform.

  • a non linear Interface Element model for thin layer high adhesive mortared masonry
    Computers & Structures, 2014
    Co-Authors: Shahid Nazir, Manicka Dhanasekar
    Abstract:

    Nonlinear constitutive relations within zero thickness Element formulation.Explicit integration within implicit finite Element modelling.Failure of high adhesive thin layer mortared masonry under biaxial loading. A nonlinear Interface Element modelling method is formulated for the prediction of deformation and failure of high adhesive thin layer polymer mortared masonry exhibiting failure of units and mortar. Plastic flow vectors are explicitly integrated within the implicit finite Element framework instead of relying on predictor-corrector like approaches. The method is calibrated using experimental data from uniaxial compression, shear triplet and flexural beam tests. The model is validated using a thin layer mortared masonry shear wall, whose experimental datasets are reported in the literature and is used to examine the behaviour of thin layer mortared masonry under biaxial loading.

  • a non linear Interface Element model for thin layer high adhesive mortared masonry
    Science & Engineering Faculty, 2014
    Co-Authors: Shahid Nazir, Manicka Dhanasekar
    Abstract:

    A nonlinear Interface Element modelling method is formulated for the prediction of deformation and failure of high adhesive thin layer polymer mortared masonry exhibiting failure of units and mortar. Plastic flow vectors are explicitly integrated within the implicit finite Element framework instead of relying on predictor–corrector like approaches. The method is calibrated using experimental data from uniaxial compression, shear triplet and flexural beam tests. The model is validated using a thin layer mortared masonry shear wall, whose experimental datasets are reported in the literature and is used to examine the behaviour of thin layer mortared masonry under biaxial loading.

Hajime Serizawa - One of the best experts on this subject based on the ideXlab platform.

  • Basic analysis of microstructural fracture behavior in structural materials by using FEM with Interface Element
    Procedia Engineering, 2011
    Co-Authors: Hajime Serizawa, Seigo Tomiyama, Tsuyoshi Hajima, Hidekazu Murakawa
    Abstract:

    Abstract A new finite Element method with the Interface Element was developed for examining the microstructural fracture behavior, where the anisotropy of grain was modeled by the ordinary finite Element while both the opening and shear deformations was demonstrated by the Interface Element. From the serial computations using two-dimensional virtual polycrystalline models obtained through Voronoi tessellations, it was found that the interaction between the interaction between opening and shear deformations would be a dominant factor of the fracture processes. Also, it can be concluded that this method would be a useful tool for examining microstructural fracture behavior. © 2011 Published by Elsevier Ltd. Selection and peer-review under responsibility of ICM11

  • Preliminary Numerical Research of Microstructural Fracture Behavior in Metal by Using Interface Element
    QUARTERLY JOURNAL OF THE JAPAN WELDING SOCIETY, 2011
    Co-Authors: Seigo Tomiyama, Hajime Serizawa, Tsuyoshi Hajima, Hidekazu Murakawa
    Abstract:

    In order to demonstrate not only the deformation of grain but also the opening and/or sliding at grain boundary, the Interface Element was introduced into the ordinary finite Element method, and this numerical method was applied for examining the microstructural fracture behavior in two-dimensional ideal microstructure obtained through Voronoi tessellations. As for the grain, the anisotropy in elastic modulus due to the grain orientation was taken into account, while the fracture strength at grain boundary was assumed to be related to the boundary energy which could be determined by the atomic disorder at the boundary. From the serial computational results for examining the influences of elastic properties in grain (isotropy and anisotropy), mechanical property at grain boundary (interaction between opening and sliding deformation), and grain configurations, it was revealed that all the factors varied in this research might affect the microstructural fracture behavior. Also, it can be concluded that this numerical method with the Interface Element can be useful for demonstrating the microstructural fracture behavior including the deformation at grain boundary.

  • Prediction of Pear-shaped Bead Cracking Under Full Penetration Welding of T-Joints Using Temperature Dependent Interface Element
    QUARTERLY JOURNAL OF THE JAPAN WELDING SOCIETY, 2009
    Co-Authors: Masakazu Shibahara, Hajime Serizawa, Shinsuke Ito, Kohei Nakata, Shinji Takaba, Koji Masaoka, Hidekazu Murakawa
    Abstract:

    After the experience of Hanshin-Awaji Earthquake, demands for full penetration welding joint with large plate thickness have been increased to improve the performance of bridges under severe earthquake. At the same time, the full penetrated T-joints without significant defects are required from the fatigue strength point of view. In case of conventional methods, removable backing material or back gouging are employed. When the removable backing material is used, root openings are required and assembly process becomes complicated. The gouging produces large noise and fume which are not welcome for good working environment. To achieve defect free full penetration T-joint without environmental problem, high current pulsed MAG welding is introduced as an alternative method. By using this welding method, the plate with thickness from 15 to 30 mm can be welded without back gouging. It is reported that no welding defect occurs when the plate thickness is less than 17mm1). However, when the plate thickness is over 25 mm, the pear-shaped bead cracking were sometimes generated if appropriate welding conditions are not selected. Therefore, in order to apply this welding method for the construction of bridges, it is necessary to clarify the welding conditions which can prevent the formation of pear-shaped bead cracking.In this study, the influence of the welding conditions on the formation of pear-shaped bead cracking is examined through the experiments of the full penetration welding of T-joints. And the same problems are analyzed using Finite Element Method. The formation and growth of pear-shaped bead crack in T-joints welded by full penetration high current pulsed MAG welding can be simulated using temperature dependent Interface Element which is introduced in the thermal-elastic-plastic FEM analysis.Results of experiments show that the pear-shaped bead cracking is not formed when the heat input is greater than 2,500 J/mm or when the penetration bead is formed. However, both large heat input and large penetration bead (deep penetration compared to the penetration width) have negative influence on hot crack formation according to the commonly accepted knowledge. To understand these experimental results, FEM simulations are conducted and influences of heat inputs and size of penetration bead are investigated.

  • Numerical Analysis of Mechanical Test Methods for Evaluating Shear Strength of Joint by Using Interface Element
    Key Engineering Materials, 2007
    Co-Authors: Hajime Serizawa, Kazuaki Katayama, Charles A. Lewinsohn, Mrityunjay Singh, Hidekazu Murakawa
    Abstract:

    As examples of the most typical methods to determine the shear strength of SiC/SiC composite joints, the tensile test of lap joined composite and the asymmetrical four point bending test of butt joined composite were analyzed by using finite Element method with the Interface Element. From the calculation results, it was revealed that the strength in the tensile test was strongly influenced by the residual stress as the increase of the joint layer thickness. In the case of asymmetrical bending test, it was found that the crack initiation point would move due to the residual stress and the strength was also affected by the joint layer thickness.

  • Numerical Analysis of Test Methods for Evaluating Shear Strength of Ceramic Composite Joints Using Interface Element
    Materials Science Forum, 2007
    Co-Authors: Hajime Serizawa, Charles A. Lewinsohn, Mrityunjay Singh, Hidekazu Murakawa
    Abstract:

    As examples of the most typical methods to determine the shear strength of SiC/SiC composite joints, the asymmetrical four point bending test of butt joined composite, the tensile test of lap joined composite and the compressive test of double-notched composite joint were analyzed by using finite Element method with the Interface Element. From the calculation results, it was found that the shear strength in the asymmetrical bending test was controlled by both the surface energy and the shear strength at the Interface regardless of their combination although the strength in the tensile test or the compressive test was governed by the surface energy when the shear strength was large. Also, it was revealed that the apparent shear strength of the composite joint obtained experimentally might be affected by the combination of the surface energy and the shear strength at the Interface.

Shahid Nazir - One of the best experts on this subject based on the ideXlab platform.

  • a non linear Interface Element model for thin layer high adhesive mortared masonry
    Computers & Structures, 2014
    Co-Authors: Shahid Nazir, Manicka Dhanasekar
    Abstract:

    Nonlinear constitutive relations within zero thickness Element formulation.Explicit integration within implicit finite Element modelling.Failure of high adhesive thin layer mortared masonry under biaxial loading. A nonlinear Interface Element modelling method is formulated for the prediction of deformation and failure of high adhesive thin layer polymer mortared masonry exhibiting failure of units and mortar. Plastic flow vectors are explicitly integrated within the implicit finite Element framework instead of relying on predictor-corrector like approaches. The method is calibrated using experimental data from uniaxial compression, shear triplet and flexural beam tests. The model is validated using a thin layer mortared masonry shear wall, whose experimental datasets are reported in the literature and is used to examine the behaviour of thin layer mortared masonry under biaxial loading.

  • a non linear Interface Element model for thin layer high adhesive mortared masonry
    Science & Engineering Faculty, 2014
    Co-Authors: Shahid Nazir, Manicka Dhanasekar
    Abstract:

    A nonlinear Interface Element modelling method is formulated for the prediction of deformation and failure of high adhesive thin layer polymer mortared masonry exhibiting failure of units and mortar. Plastic flow vectors are explicitly integrated within the implicit finite Element framework instead of relying on predictor–corrector like approaches. The method is calibrated using experimental data from uniaxial compression, shear triplet and flexural beam tests. The model is validated using a thin layer mortared masonry shear wall, whose experimental datasets are reported in the literature and is used to examine the behaviour of thin layer mortared masonry under biaxial loading.

Shah M. Yunus - One of the best experts on this subject based on the ideXlab platform.

  • A new acoustic Interface Element for fluid‐structure interaction problems
    International Journal for Numerical Methods in Engineering, 1992
    Co-Authors: Chandheeb Rajakumar, Ashraf Ali, Shah M. Yunus
    Abstract:

    A new comprehensive acoustic 2-D Interface Element capable of coupling the boundary Element (BE) and finite Element (FE) discretizations has been formulated for fluid-structure interaction problems. The Helmholtz equation governing the acoustic pressure in a fluid is discretized using the BE method and coupled to the FE discretization of a vibrating structure that is in contact with the fluid. Since the BE method naturally maps the infinite fluid domain into finite node points on the fluid-structure Interface the formulation is especially useful for problems where the fluid domain extends to infinity. Details of the BE matrix computation process adapted to FE code architecture are included for easy incorporation of the Interface Element in FE codes. The Interface Element has been used to solve a few simple fluid-structure problems to demonstrate the validity of the formulation. Also, the vibration response of a submerged cylindrical shell has been computed and compared with the results from an entirely finite Element formulation.