• Journal of Korean Society of Steel Construction
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• v.23 no.3
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• pp.317-326
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• 2011

Today there is a growing range of applications for Concrete-Filled Steel Tube (CFT) member because of its superior performance. Ductility estimation test of concrete-filled seismic resistant steel tubular columns, subjected to axial and cyclic lateral load, was carried out in this study. Seismic resistant steel tubes are manufactured using SN400B plates by a two-seam welding at center of the column width for cold press-formed shape plates of two pieces. A total of eight specimens were manufactured and tested with the parameters of width-thickness ratio of steel tubular column, axial load ratio, and loading conditions to act axial and cyclic lateral load two dynamic actuators were used. From test results, flexural strength, deformation capacity, energy dissipation capacity, and ductility behavior of columns were analyzed.

• Proceedings of the KWS Conference
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• 2010.05a
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• pp.60-60
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• 2010

Since the curved hull plate was made by a series of manufacturing process including cold bending, manual local heating and correction work, the accuracy of curved plate strongly depends on the proficiency of worker. So the demands on the automatic local heating system for curved hull plate have continuously increased and the various researches relevant to it have been performed. Generally, the heat sources used for local heating were flame and induction heat. In terms of initial cost, flame heating is in a better favorable position than induction heating. However, from the viewpoint of the control of heat, induction heating has more advantage. So the various researches related to apply the induction heating to the automatic forming system has been performed. The purpose of this study is to establish the proper capacity of high frequency induction heating system for forming the curved hull plate. In order to do it, the proper coil shape for local heating was designed and the efficiency of induction heating system was determined by comparing of temperature results obtained by FEA and experiment. With the results, the extensive FEA was performed to identify the effect of heated plate dimension, cooling method and the capacity of induction heating system on the amount of heat loss introduced by induction heating. Based on the results, the proper capacity of high frequency induction heating system was proposed.

• Journal of the Earthquake Engineering Society of Korea
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• v.18 no.1
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• pp.63-71
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• 2014

This study presents an experimental study of the structural behavior for steel plate-concrete column-to-steel girder connections. Experiments were carried out to investigate the moment-rotation characteristics, failure behavior and ultimate moment capacity of these connections. The results of this experimental study involving three welded moment-resisting connections subjected to cyclic loading are presented. The specimens were fabricated at full scale to evaluate their hysteretic behavior. A description of the test specimens, the details of the joint, the test system and the testing methods are described. The test results showed that the structural behavior of these composite connections was influenced by the connection details.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.10a
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• pp.39-42
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• 2003

Steam Generator has been manufactured by welding process after partial manufacturing of various steel forgings such as shell, head and tube sheet. Usually, these steel forgings are made by open die forging process. After steel melting and ingot making, open die forging has been carried out to get a good quality which means high soundness and homogeniety of the steel forgings by using high capacity hydraulic press. This paper introduced open die forging development status of the large steel forgings which is used for the steam generator of 1,400MW next generation nuclear power plant.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1993.10a
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• pp.575-581
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• 1993

This paper deals with analysis of articulated robot manipulator used for Arc welding and Material handling. Compared with present robot of which weight holding capacity is 6kg, this robot shows wider and symmetric working range for it's serial type mechanism. The link length is determined to have widest working range by using optimal simulation. To reduce body's weight, small AC servo motor is adopted and driving peak torque exerted at each joint is reduced by using dynamic analysis. So it is possible to reduce body's weight by 40% compared with the same class's robot and get wider working range. And by adopting modular design concept, each axis is designed to be changed easily for user's special need and repair.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.05a
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• pp.787-792
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• 2002

The voided slab have many advantages, light weight, high load-distribution capacity, low cost and beautiful appearance, etc. But they have also many cracks due to difficulties in designs and construction, analysis, shrinkage, installation and rising force of voided tube. This paper presents the retrofit effects with steel plate(SP)/carbon fiber sheet(CFS) of RC voided slab. As a results of this study, it proved that the strip pattern has to be profitable than full-face pattern in performance such as crack, ultimate loads, stiffness. Retrofit length has many influence on retrofit effects, as the length increases, performance and stability of end blocks higher. Also, it proved that the retrofit on full-section has to be profitable than voided-section in performance, and the overlay length of CFS is desirable to extent approximately and welding(V-cut) has to be efficient than anchors in SP connection. But the kinds of end block and anchor has not influence on retrofit effects.

• Journal of the Korean Society of Industry Convergence
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• v.21 no.3
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• pp.133-139
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• 2018

Precipitator is the most widespread device used to separate dust particles from the exhaust gas. In the shipyard, welding umbrellas, spark protection covers, and ventilators are not purchased and used for the work place to capture the flames and high temperature metal dust generated during the gardening process. In particular, a thorough analysis of design factors, such as capture rate, collection capacity calculation, filter speed, and materials selection, is required since spatial constraints are followed by structures, etc. In this study, conceived to address problems such as this cyclone and filtration filter system that combines all-in-one gausing collector prototype. Assessed through interpretation through the validity of the design and reliability.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.756-759
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• 2003

Steam Generator is one of the most important structural part of nuclear power plant. It is manufactured by welding process of various steel forgings such as shell, head, torus and tube sheet. These steel forgings have been made by open die forging process. After steel melting and ingot making, open die forging has been carried out to get a good quality which means high soundness and homogeniety of the steel forgings by using high capacity hydraulic press. This paper introduced open die forging status and investigated forging method of the ultra large steel forgings which is used for the steam generator of 1000MW nuclear power plant. For the same thing. the type of steel forgings consisting steam generator is classified by shell, head, torus and tube sheet. And corresponding forging processes of the steel forgings have been investigated.

• 전기의세계
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• v.21 no.4
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• pp.27-38
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• 1972

This paper discusses the characteristics about the ignition of D.C. main discharge is a plasma jet generator, manufactured for trial as non-transferred type, when the electrical energy appropriate to the ignition is supplied to the gap between the electrodes by using advance discharge of attenuating high frequency voltage generated by a high frequency oscillator with mercury spark gap. These characteristics are under the influences of (a) the length of mercury gap in high frequency oscillator and the quantity of hydrogen flow supplied to it, (b) the condenser capacity of the high frequency oscillator circuit, (c) the length of plasma jet torch in D.C. main discharge circuit and the quantity of argon flow supplied to it, (d) the circuit constants of D.C. main discharge circuit. The results for these characteristics, obtained by this research, are considered to be helpful to the designs for the ignition of a plasma jet as well as the welding arc stabilizer by high frequency discharge and the high frequency arc welder.

• Structural Engineering and Mechanics
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• v.54 no.5
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• pp.999-1016
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• 2015

In this paper, we introduce a new method for assembly of shipbuilding blocks at sea and present its feasibility focusing on structural safety. The core concept of this method is to assemble ship building blocks by use of bolting, gluing and welding techniques at sea without dock facilities. Due to its independence of dock facilities, shipyard construction capability could be increased considerably by the proposed method. To show the structural safety of this method, a bulk carrier and an oil tanker were employed, and we investigated the structural behavior of those ships to which the new block assembly method was applied. The ship hull models attached with connective parts are analyzed in detail through finite element analyses, and the cargo capacity of the bulk carrier is briefly discussed as well. The results of these studies show the potential for applying this new block assembly method to practical shipbuilding.