Environmentally Materials and Components Center

Jeonju, South Korea

Environmentally Materials and Components Center

Jeonju, South Korea
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Shim J.Y.,Environmentally Materials and Components Center | Kang B.Y.,Environmentally Materials and Components Center | Kim I.S.,Mokpo National University | Kang M.J.,Advanced Welding and Joining Technology Service Center | And 2 more authors.
Advanced Materials Research | Year: 2010

Recent trends of welding system have been focused on the development of new process in order to achieve better quality, higher productivity and friendly to the environmentally in welding process. The Magnetic Pulse Welding(MPW) process is based on the principle of a tremendous amount of energy compressed and discharged for an extremely short period of time. The purpose of this paper is to investigate welding characteristics according to the distributions of an electromagnetic force on the weldment using a finite element method and to find the optimal process parameters such as input current and frequency. To successfully accomplish this objective, a 2-dimensional axisymmetric electromagnetic numerical model has firstly been developed. The equation was solved using a general electromagnetic mechanics computer program, ANSYS code. The comparison between the calculated and measured results has been carried out to verify the developed system. © (2010) Trans Tech Publications.

Thao D.T.,Mokpo National University | Kim I.S.,Mokpo National University | Na H.H.,Mokpo National University | Jung S.M.,Mokpo National University | Shim J.Y.,Environmentally Materials and Components Center
International Journal of Advanced Manufacturing Technology | Year: 2014

Gas metal arc (GMA) welding process has widely been employed due to the wide range of applications, cheap consumables, and easy handling. In order to achieve a high level of welding performance and quality, a suitable model is required to investigate the characteristics of the effects of process parameters on the bead geometry in the GMA welding process. This paper is to represent new algorithms to predict process parameters on top-bead width in robotic GMA welding process. The models have been developed, linear, curvilinear, and intelligent model, based on full factorial design with two replications. Regression analysis was employed for optimization of the coefficients of linear and curvilinear models, while genetic algorithm (GA) was utilized to estimate the coefficients of an intelligent model. Not only the fitting of these models was checked and compared by using a variance test (analysis of variance (ANOVA)) but also the prediction on top-bead width using the developed models was carried out based on the additional experiments. The developed models were employed to investigate the characteristic between process parameters and top-bead width. Resulting solutions and graphical representation showed that the intelligent model developed can be employed for prediction of bead geometry in GMA welding process. © 2014 Springer-Verlag London.

Seo J.H.,Mokpo National University | Kim I.S.,Mokpo National University | Kang B.Y.,Environmentally Materials and Components Center | Shim J.Y.,Environmentally Materials and Components Center | And 2 more authors.
Advanced Materials Research | Year: 2011

Industries such as gas, oil, petrochemical, chemical, and electric power have generally employed for the operation and used to enlarge the equipment or structures that require a high capital investment. In order to meet these requirements, the industries are increasingly moved toward saving the experimental verifications and computer simulation. Therefore industries to reduce the maintenance costs without compromising operational safety have been forced on finding better and more efficient methods to inspect their equipment and structures. It was motivated to meet the industrial needs and to secure and maintain the institute's technical initiative and leadership in the development of this new and exciting technology. Also, the system with many sensors could be detected the weld defects, and was useful for real-time monitoring. This paper is focused on the development of the real-time non-contract monitoring system as an efficient tool for the experimental study of weld defects based on the relationship between the measured voltage and input parameters. The monitoring technology involves the use of Ms S (Magnetostrictive Sensors) for the generation and detection of the guided waves. The developed system was employed to the experimental study in order to fine the weld defects for steel object with artificial defects used in the welding field. © (2011) Trans Tech Publications, Switzerland.

Lee J.H.,Mokpo National University | Kim I.S.,Mokpo National University | Jang H.K.,Doosan Infracore | Kim H.J.,Reliablility Center for Metallic Materials | And 4 more authors.
AIP Conference Proceedings | Year: 2010

Since prediction and control of welding deformation are one of an important problems connected with reliability of the manufactured structures, welding deformation should be measured and controlled with quickly and actively. Also, welding variables which have lots of effects on welding deformation such as arc voltage, welding current and welding speed can also be controlled. This study focuses on development of a simple 2D(a two-dimension) FEM(Finite Element Method) to calculate not only the transient thermal histories, but also the sizes of Fusion Zone(HZ) and Heat-Affected Zone (HAZ) in multi-pass arc welding including the butt weld type with dissimilar thickness, and to develop the new model for finding the parameters of Godak's heat source model based on a GA(Genetic Algorithm). The developed model included a GA program using MATLB and GA toolbox, and a batch mode thermal model using ANSYS software. The thermal model was verified by comparison with Goldak's work and the molten zone section from obtained the experimental data. In addition, the developed model could be applied the various welding types in order to employ for the manufacturing industries. © 2010 American Institute of Physics.

Shim J.-Y.,Environmentally Materials and Components Center | Kim I.-S.,Mokpo National University | Kang M.-J.,Advanced Welding and Joining Technology | Kim I.-J.,Environmentally Materials and Components Center | And 2 more authors.
Materials Transactions | Year: 2011

Magnetic Pulse Welding (MPW) is not only one of the most useful welding processes for the dissimilar metal joining which uses cylindrical materials such as a pipe, but also a new technology for metal welding by means of repulsive force on account of the interaction between magnetic part of working coil and current induced in an outer pipe. Since the factors effected on quality of MPW are the charged voltage, the gap between inner pipe and outer pipes and a thickness of an outer pipe, the this study was focused on the investigation of the effect of process parameters and development of the mathematical model for the prediction on a quality of joint using Response Surface Method (RSM). To achieve the objective, the MPW equipment manufactured by WELDMATE CO., LTD. has been employed and applied for the materials such as the Al 1070, SM45C for Al and steel pipe respectively. After the sequent experiment, leakage test has been done to verify efficiency of the welding. The experimental values have been shown the good agreement with the predicted ones, indicating suitability of mathematical model employed. It is concluded that the gap between outer pipe and inner rod is one of major process parameters for influence on quality of joint while Al/steel pipe welding using the MPW. © 2011 The Japan Institute of Light Metals.

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