The Experts below are selected from a list of 243 Experts worldwide ranked by ideXlab platform

Hu Zhang - One of the best experts on this subject based on the ideXlab platform.

  • numerical simulation of three dimension stress field in double sided double arc multipass welding process
    Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2009
    Co-Authors: Hu Zhang, Guifeng Zhang, Laijun Wu
    Abstract:

    Abstract A new High-efficiency method for welding thick plates of low-alloy High-Tensile Steel which does not require back chipping – double-sided arc welding (DSAW) – is provided in this paper. Backing run adopts double-sided pulse gas tungsten arc welding, and other passes adopt double-sided gas metal arc welding. Three-dimensional numerical models of DSAW with 50 mm plates are developed to predict the stress distribution by using finite-element analysis, computer parallel processing technology and multiple jobs design, and are compared with single arc welding (SAW). The analysis of the interpass stresses indicates that the stresses of the back and cover pass are to be regarded as the key point in multipass welding. To verify the calculated results, the residual stresses and transient temperature of back run weld measured individually agree approximately with the calculated results, which illustrates that the backing run and residual stresses of DSAW are lower than those of SAW.

Jiromaru Tsujino - One of the best experts on this subject based on the ideXlab platform.

  • Impact-reduction effect of ultrasonic vibrations on carbon fiber-reinforced polymer plate using a downsized transducer
    2017 IEEE International Ultrasonics Symposium (IUS), 2017
    Co-Authors: Atsuyuki Suzuki, Kai Kimura, Futoshi Nishimura, Jiromaru Tsujino
    Abstract:

    There are various technologies available for automobile safety. However, about 1.3 million people die each year as a result of road traffic crashes in the world. We aim to develop an impact-reduction device using ultrasonic vibrations that can change the rigidity of crushable zones instantaneously in the event of traffic crashes. We have previously reported on the deformation and impact-reduction characteristics when applying ultrasonic vibrations to several materials such as High-Tensile Steel and carbon fiber-reinforced polymer plate (CFRP). An oversized transducer increases the overall weight of the vehicle and reduces fuel economy. Therefore, it is important to downsize the impact-reduction device. The purpose of this study is to confirm the impact-reduction effect of the ultrasonic vibrations using a downsized ultrasonic transducer.

  • Impact-reduction effect of ultrasonic vibrations on carbon fiber-reinforced polymer plate using a downsized transducer
    2017 IEEE International Ultrasonics Symposium (IUS), 2017
    Co-Authors: Atsuyuki Suzuki, Kai Kimura, Futoshi Nishimura, Jiromaru Tsujino
    Abstract:

    The number of deaths caused by traffic accidents remains High, in spite of the development of many kinds of safety technologies. It is difficult to absorb the impact energy sufficiently in many cases. We suggested that the impact energy can be further absorbed by adjusting the deformation resistance of the material of the structure instantaneously. Furthermore, we developed an impact-reduction setup by using ultrasonic vibrations. It was already determined in previous studies that the deformation resistance of materials and impact force decrease by applying ultrasonic vibrations. Reducing the weight of vehicles is very significant to improve fuel efficiency. Therefore, we have reported on the deformation and impact-reduction characteristics when a downsized transducer is used. The tested material was High-Tensile Steel. Carbon fiber-reinforced polymer plate (CFRP plate) is receiving significant attention for the reduction of the weight of vehicles along with High-Tensile Steel. It is important to confirm the effect of ultrasonic vibrations on the CFRP plate using a downsized ultrasonic transducer. In this study, we used a downsized ultrasonic transducer and measured the vibration, deformation, and impact-reduction characteristics. The CFRP plate can be bent easily with the application of ultrasonic vibrations. The time elapsed before the specimens were fractured was reduced with the increase in the driving voltage. The impact force was reduced by up to 82.3% with the application of ultrasonic vibrations.

  • Impact-absorbing effect by applying ultrasonic vibrations to High-Tensile Steel plate
    2013 IEEE International Ultrasonics Symposium (IUS), 2013
    Co-Authors: Atsuyuki Suzuki, Takahiro Onitake, Kanji Ikunaka, Jiromaru Tsujino
    Abstract:

    The stress induced during the plastic deformation of metals decreases with the application of ultrasonic vibrations. This effect is currently employed in industrial operations such as bending. Now, we note that the rigidity of a traditional crushable zone does not change instantaneously. In this light, in this study, we aim to develop an impact-absorbing system by applying ultrasonic vibrations that can change the rigidity of crushable zones instantaneously in the event of a traffic accident. Ultrasonic vibrations reduce not only the stress but also the springback amount. If the decrease in the latter effectively prevents the rebound of the colliding object, damage after rebounding will be reduced. In this study, we developed an experimental device to confirm the impact-absorbing effect by applying ultrasonic vibrations to a High-Tensile Steel plate. We measured the springback amount, impact-absorbing characteristics, and so on. The springback amount was reduced by up to 43% by the application of ultrasonic vibrations. The impact force was reduced by up to 35% by the application of ultrasonic vibrations.

Jung Min Sohn - One of the best experts on this subject based on the ideXlab platform.

  • Effects of Welding Residual Stresses on High Tensile Steel Plate Ultimate Strength: Nonlinear Finite Element Method Investigations
    Journal of Offshore Mechanics and Arctic Engineering-transactions of The Asme, 2011
    Co-Authors: Jeom Kee Paik, Jung Min Sohn
    Abstract:

    The primary objective of the present paper is to examine the effects of welding residual stresses on ultimate strength of High Tensile Steel plates under axial compression in terms of their magnitude and pattern. The ANSYS nonlinear finite element method is employed for the purpose. The secondary objective of the present paper is to study a nonlinear finite element method modeling technique for welded plate structures with residual stresses. Three levels of residual stresses, namely slight, average, and severe, are considered. As another important parameter of influence on the plate ultimate strength, the plate thickness is also varied in the numerical computations to examine their role and trend. Important insights and conclusions developed from the present study are documented.

  • Effects of Welding Residual Stresses on High Tensile Steel Plate Ultimate Strength: Nonlinear Finite Element Method Investigations
    Volume 2: Structures Safety and Reliability, 2009
    Co-Authors: Jeom Kee Paik, Jung Min Sohn
    Abstract:

    The primary objective of the present paper is to examine the effects of welding residual stresses on ultimate strength of High Tensile Steel plates under axial compression in terms of their magnitude and pattern. The ANSYS nonlinear finite element method is employed for the purpose. The secondary objective of the present paper is to study a nonlinear finite element method modeling technique for welded plate structures with residual stresses. Three levels of residual stresses, namely slight, average and severe levels are considered. As another important parameter of influence on the plate ultimate strength, the plate thickness is also varied in the numerical computations to examine their role and trend. Important insights and conclusions developed from the present study are documented.Copyright © 2009 by ASME

Laijun Wu - One of the best experts on this subject based on the ideXlab platform.

  • numerical simulation of three dimension stress field in double sided double arc multipass welding process
    Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2009
    Co-Authors: Hu Zhang, Guifeng Zhang, Laijun Wu
    Abstract:

    Abstract A new High-efficiency method for welding thick plates of low-alloy High-Tensile Steel which does not require back chipping – double-sided arc welding (DSAW) – is provided in this paper. Backing run adopts double-sided pulse gas tungsten arc welding, and other passes adopt double-sided gas metal arc welding. Three-dimensional numerical models of DSAW with 50 mm plates are developed to predict the stress distribution by using finite-element analysis, computer parallel processing technology and multiple jobs design, and are compared with single arc welding (SAW). The analysis of the interpass stresses indicates that the stresses of the back and cover pass are to be regarded as the key point in multipass welding. To verify the calculated results, the residual stresses and transient temperature of back run weld measured individually agree approximately with the calculated results, which illustrates that the backing run and residual stresses of DSAW are lower than those of SAW.

Jeom Kee Paik - One of the best experts on this subject based on the ideXlab platform.

  • Test database of the mechanical properties of mild, High-Tensile and stainless Steel and aluminium alloy associated with cold temperatures and strain rates
    Ships and Offshore Structures, 2017
    Co-Authors: Jeom Kee Paik, Bo Gyeong Jung
    Abstract:

    In structural analysis and design, it is essential to define the material properties associated with the targeted structural systems. When harsh environmental or operational conditions are of primary concern, the mechanical properties of materials must be quantified by considering the effects of the conditions. The aim of this study is to develop a new test database on the mechanical properties of materials for marine applications, such as mild Steel, High-Tensile Steel, aluminium alloy 5083-O and stainless Steel 304L, focusing on the effects of cold temperatures and strain rates. Discussion of the new test database refers to extant test databases where available. Moreover, test coefficients that may be useful in the existing constitutive equations for the materials are suggested and the details of the test database are documented.

  • Effects of Welding Residual Stresses on High Tensile Steel Plate Ultimate Strength: Nonlinear Finite Element Method Investigations
    Journal of Offshore Mechanics and Arctic Engineering-transactions of The Asme, 2011
    Co-Authors: Jeom Kee Paik, Jung Min Sohn
    Abstract:

    The primary objective of the present paper is to examine the effects of welding residual stresses on ultimate strength of High Tensile Steel plates under axial compression in terms of their magnitude and pattern. The ANSYS nonlinear finite element method is employed for the purpose. The secondary objective of the present paper is to study a nonlinear finite element method modeling technique for welded plate structures with residual stresses. Three levels of residual stresses, namely slight, average, and severe, are considered. As another important parameter of influence on the plate ultimate strength, the plate thickness is also varied in the numerical computations to examine their role and trend. Important insights and conclusions developed from the present study are documented.

  • Effects of Welding Residual Stresses on High Tensile Steel Plate Ultimate Strength: Nonlinear Finite Element Method Investigations
    Volume 2: Structures Safety and Reliability, 2009
    Co-Authors: Jeom Kee Paik, Jung Min Sohn
    Abstract:

    The primary objective of the present paper is to examine the effects of welding residual stresses on ultimate strength of High Tensile Steel plates under axial compression in terms of their magnitude and pattern. The ANSYS nonlinear finite element method is employed for the purpose. The secondary objective of the present paper is to study a nonlinear finite element method modeling technique for welded plate structures with residual stresses. Three levels of residual stresses, namely slight, average and severe levels are considered. As another important parameter of influence on the plate ultimate strength, the plate thickness is also varied in the numerical computations to examine their role and trend. Important insights and conclusions developed from the present study are documented.Copyright © 2009 by ASME