The Experts below are selected from a list of 246 Experts worldwide ranked by ideXlab platform
G R Wang - One of the best experts on this subject based on the ideXlab platform.
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vision based seam tracking system for Underwater flux cored arc Welding
Science and Technology of Welding and Joining, 2006Co-Authors: G R WangAbstract:AbstractManual Underwater Welding is usually time consuming, expensive and hard to perform because of the rigorous Underwater environment. Automatic Underwater Welding can be performed faster at less cost and with higher quality. An automatic seam tracking system for Underwater flux cored arc Welding has been developed. It consists of a vision sensing module, a seam recognition module, a fuzzy controller (FC) and an X–Y travel platform. The vision sensing module can capture clear seam images during Welding, successfully resolving the problem of Welding arc interference during Underwater flux cored arc Welding. The seam recognition module filters, enhances and thresholds the seam images and then recognises the seam deviation angle with a three layer back propagation neural network. The FC outputs the control parameters according to the seam deviation angle and then controls the X–Y platform to drive the torch to the centre of the seam. In this study, three different welds were considered: a straight line, ...
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Vision based seam tracking system for Underwater flux cored arc Welding
Science and Technology of Welding and Joining, 2006Co-Authors: Y.-h. Shi, G R WangAbstract:Manual Underwater Welding is usually time consuming, expensive and hard to perform because of the rigorous Underwater environment. Automatic Underwater Welding can be performed faster at less cost and with higher quality. An automatic seam tracking system for Underwater flux cored arc Welding has been developed. It consists of a vision sensing module, a seam recognition module, a fuzzy controller (FC) and an X-Vtravel platform. The vision sensing module can capture clear seam images during Welding, successfully resolving the problem of Welding arc Interference during Underwater flux cored arc Welding. The seam recognition module filters, enhances and thresholds the seam images and then recognises the seam deviation angle with a three layer back propagation neural network. The FC outputs the control parameters according to the seam deviation angle and then controls the X-Y platform to drive the torch to the centre of the seam. In this study, three different welds were considered: a straight line, a kinked straight line and an S curved line. These welds were tracked real timely during Underwater flux cored arc Welding. The results show that this seam tracking system can meet the requirements of the automatic Underwater flux cored arc Welding. © 2006 Institute of Materials, Minerals and Mining.
Jicai Feng - One of the best experts on this subject based on the ideXlab platform.
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effect of boric acid on metal transfer mode of Underwater flux cored wire wet Welding
Journal of Materials Processing Technology, 2015Co-Authors: Yongpeng Du, Yunlong Fu, Jicai FengAbstract:Abstract For obtaining high quality of Underwater Welding repairing for nuclear power equipments, the influence of boric acid on metal transfer process of Underwater flux-cored wire wet Welding in boric acid solution is explored by an X-ray transmission system. The research results show that the mixed repelled globular transfer and solid short circuit transfer mode and the mixed repelled globular transfer and surface tension transfer mode are two kinds of main metal transfer modes during Underwater Welding in boric acid solution. The proportion of the mixed repelled globular transfer and surface tension transfer mode is increasing with the increasing of concentration of boric acid solution, which is caused by the difference of force condition of the droplet.
R. Hamann - One of the best experts on this subject based on the ideXlab platform.
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Modelling of wet Plasma-MIG Underwater Welding process for calculation of the temperature field
Journal of Applied Mathematics and Mechanics, 1996Co-Authors: R. Hamann, O. Mahrenholtz, J. BartzschAbstract:A concept for the numerical computation of the temperature field in a weld body for the wet Plasma-MIG Underwater Welding process is presented. The necessary models for the approximation of the heat input by arc and the heat flux to water are described. The accuracy of the concept is demonstrated by the sample of a surface weld.
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Influence of wet Underwater Welding on fracture values
1995Co-Authors: L. Lindhorst, O. Mahrenholtz, R. Hamann, M. KocakAbstract:The fracture behavior of welds is influenced by residual stresses. The influence of residual stresses on fracture parameters is investigated through the comparison of wet Underwater welds, dry welds and welds without residual stresses. The fracture parameters for a sharp, stationary crack on the surface of a bead on plate weld under bending are determined by the finite element method. The geometric influence of weld on fracture parameters is investigated. The stress intensity factor for linear elastic fracture mechanics, the J-integral and the crack tip opening displacement for plastic fracture mechanics are calculated. The material behavior is assumed as linear elastic or linear elastic/ideal plastic or elastic plastic with multilinear isotropic hardening. The numerical data are compared with the experiments.
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ON THE INFLUENCE OF THE SURFACE HEAT TRANSFER COEFFICIENT ON WET Underwater WELDS
1994Co-Authors: R. Hamann, O. MahrenholtzAbstract:This paper deals with the influence of the surface heat transfer on the temperature distribution during wet Underwater Welding. A model for the heat-transfer-coefficient on a horizontal plate considering different effects is presented. The influence of undercooled boiling, surface orientation and heater material on the temperature course are discussed. Welding experiments were performed on low carbon steel plates in a shallow water basin using Plasma-MIG Underwater Welding technique. For the numerical simulation of the Welding process a new Welding model has been developed for the Plasma-MIG Underwater Welding technique. The temperature problem is solved using finite element method. The numerical and experimental data are compared.
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Thermomechanical simulation of Underwater Welding processes
Archive of Applied Mechanics, 1992Co-Authors: J. Ronda, O. Mahrenholtz, R. HamannAbstract:The Underwater Welding problem has been formulated for the thermoelastic body as the sequence of the thermal free-boundary problem and the thermomechanical contact problem. The thermal free-boundary problem is discussed due to accounting for phase transformations. The contact problem is considered to establish interactions between a weld and elements of weldment and residual stresses inside the weldment.
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Thermomechanical simulation of Underwater Welding processes
Archive of Applied Mechanics, 1992Co-Authors: J. Ronda, O. Mahrenholtz, R. HamannAbstract:The Underwater Welding problem has been formulated for the thermoelastic body as the sequence of the thermal free-boundary problem and the thermomechanical contact problem. The thermal free-boundary problem is discussed due to accounting for phase transformations. The contact problem is considered to establish interactions between a weld and elements of weldment and residual stresses inside the weldment. Das Unterwasser-Schweißen wird als Folge eines thermischen Problems für einen thermoelastischen Körper mit freien Oberflächen und eines thermomechanischen Kontaktproblems formuliert. Das thermische Problem mit freien Oberflächen wird zwecks Berücksichtigung von Phasentransformationen erörtert. Das Kontaktproblem wird behandelt, um Wechselwirkungen zwischen Schweißnaht, verschweißten Teilen und Eigenspannungen zu ergründen.
O. Mahrenholtz - One of the best experts on this subject based on the ideXlab platform.
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On the influence of wet Underwater Welding on CTOD-δ5
International Journal of Fracture, 1999Co-Authors: L. Lindhorst, O. MahrenholtzAbstract:The influence of wet Underwater Welding on the crack tip opening displacement CTOD-δ_5 is investigated in this paper. The Welding process is numerically simulated. The instationary temperature field and Welding residual stresses are calculated using the finite element method (FEM). The crack tip opening displacement for a sharp, stationary crack on the surface of a bead-on-plate weld under bending is determined. The results for an Underwater wet welded specimen and a dry welded specimen are compared. The Welding residual stresses are considered in the 3D fracture mechanics FE calculation as well as the material heterogeneity due to the different material properties of weld metal, heat-affected zone and base metal.
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Modelling of wet Plasma-MIG Underwater Welding process for calculation of the temperature field
Journal of Applied Mathematics and Mechanics, 1996Co-Authors: R. Hamann, O. Mahrenholtz, J. BartzschAbstract:A concept for the numerical computation of the temperature field in a weld body for the wet Plasma-MIG Underwater Welding process is presented. The necessary models for the approximation of the heat input by arc and the heat flux to water are described. The accuracy of the concept is demonstrated by the sample of a surface weld.
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Influence of wet Underwater Welding on fracture values
1995Co-Authors: L. Lindhorst, O. Mahrenholtz, R. Hamann, M. KocakAbstract:The fracture behavior of welds is influenced by residual stresses. The influence of residual stresses on fracture parameters is investigated through the comparison of wet Underwater welds, dry welds and welds without residual stresses. The fracture parameters for a sharp, stationary crack on the surface of a bead on plate weld under bending are determined by the finite element method. The geometric influence of weld on fracture parameters is investigated. The stress intensity factor for linear elastic fracture mechanics, the J-integral and the crack tip opening displacement for plastic fracture mechanics are calculated. The material behavior is assumed as linear elastic or linear elastic/ideal plastic or elastic plastic with multilinear isotropic hardening. The numerical data are compared with the experiments.
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ON THE INFLUENCE OF THE SURFACE HEAT TRANSFER COEFFICIENT ON WET Underwater WELDS
1994Co-Authors: R. Hamann, O. MahrenholtzAbstract:This paper deals with the influence of the surface heat transfer on the temperature distribution during wet Underwater Welding. A model for the heat-transfer-coefficient on a horizontal plate considering different effects is presented. The influence of undercooled boiling, surface orientation and heater material on the temperature course are discussed. Welding experiments were performed on low carbon steel plates in a shallow water basin using Plasma-MIG Underwater Welding technique. For the numerical simulation of the Welding process a new Welding model has been developed for the Plasma-MIG Underwater Welding technique. The temperature problem is solved using finite element method. The numerical and experimental data are compared.
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Thermomechanical simulation of Underwater Welding processes
Archive of Applied Mechanics, 1992Co-Authors: J. Ronda, O. Mahrenholtz, R. HamannAbstract:The Underwater Welding problem has been formulated for the thermoelastic body as the sequence of the thermal free-boundary problem and the thermomechanical contact problem. The thermal free-boundary problem is discussed due to accounting for phase transformations. The contact problem is considered to establish interactions between a weld and elements of weldment and residual stresses inside the weldment.
Yongpeng Du - One of the best experts on this subject based on the ideXlab platform.
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effect of boric acid on metal transfer mode of Underwater flux cored wire wet Welding
Journal of Materials Processing Technology, 2015Co-Authors: Yongpeng Du, Yunlong Fu, Jicai FengAbstract:Abstract For obtaining high quality of Underwater Welding repairing for nuclear power equipments, the influence of boric acid on metal transfer process of Underwater flux-cored wire wet Welding in boric acid solution is explored by an X-ray transmission system. The research results show that the mixed repelled globular transfer and solid short circuit transfer mode and the mixed repelled globular transfer and surface tension transfer mode are two kinds of main metal transfer modes during Underwater Welding in boric acid solution. The proportion of the mixed repelled globular transfer and surface tension transfer mode is increasing with the increasing of concentration of boric acid solution, which is caused by the difference of force condition of the droplet.
