• Journal of Korean Association for Spatial Structures
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• v.4 no.4 s.14
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• pp.129-136
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• 2004

Almost the steel bridges are manufactured and constructed by using weld process. The welding is necessary for connecting the flange, web and stiffener of steel bridges. However, residual stress and welding deformation producted by welding is a causes of decreasing the load carrying capacity of steel bridges. therefore, it is need to consider the initial stresses by welding when design the steel bridge. However, the influence of initial stress producted by welding on load carrying capacity of steel bridges is not elucidated. In this paper, the initial stress state on the flange, web and stiffener of steel bridges are clarified by carrying out 3-dimensional non-steady heat conduction analysis and 3-dimensional thermal elastic-plastic analysis. The influence of initial stress by welding on load carrying capacity of steel bridges is clarified by carrying out 3-dimensional elastic-plastic finite element analysis using finite deformation theory.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2005.11a
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• pp.226-227
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• 2005

In this study, it was investigated about endurance and fatigue crack propagation rate of according to welding methods of SMAW and FCAW commonly using for welding structures in present. Endurance limits carried out highly in the order of SMAW, FCAW and fatigue crack propagation rate out lowly in the order of SMAW, FCAW. By these results, it is needed to used SMAW welding methods for welding structures with small welding capacity and FCAW methods for large welding structures after consideration about economic gains and operation efficiency of welding. Fatigue crack propagation rate is more effected by strength of welding materials than endurance limit of welding materials according to welding methods..

• Proceedings of the Korea Concrete Institute Conference
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• 1999.04a
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• pp.553-558
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• 1999

As a process of development of composite beam-column connection system, structural tests have been conducted to verify moment resisting performance of the system. The tests have been proceeded by two steps, the first being welding performance test of the steel connection rod and stiffners, and the second overall moment resisting capacity of the fuly assembled system. Ten welding test specimens and four prototype specimens have been used in the test. Good structural performance of welding test specimens has been observed without any single welding failure, and sufficient moment resisting capacity has been proved from the overall performance test, with the moment magnitude in excess of the calculated plastic moment.

• Steel and Composite Structures
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• v.11 no.3
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• pp.225-232
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• 2011

In this study, the deflection and deformation behaviours of IPN80 steel beam and column were investigated under the different industrial loads. Single-sided welds were applied to IPN80 steel beams using shielded metal arc (SMAW) and metal inert gas welding (MIG) method in the form of T-type. After that, the performance of SMAW and MIG welded joints were identified using beam bending test under 500 and 3000 N loads. SMAW and MIG methods were compared with each other to understand the deflection and deformation behaviours of the welded steel structures. Lower deformation and deflection were obtained in MIG welded steel beams. The results show that, steel beams welded MIG method has higher load capacity than SMAW welded ones. MIG welding method is more reliable than the SMAW method for the combining performance and load capacity.

• Journal of Welding and Joining
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• v.24 no.1
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• pp.33-36
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• 2006

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.135-137
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• 2004

In this study we'll deal with the small-sized metalized film capacitors with large capacity which head have $5mm{\times}5mm{\times}2.5mm$ dimension. The lead wire is used to weld at both sides of capacitors. At that time the position gap between the welding machine and lead wire supplier would cause the welding error. Also, during the tapping processing of metalized film capacitors, the interval error among the capacitors, the length error of lead frame attached at the capacitors, and the straightness distortion of the lead frame could happen. As mentioned, four kinds of error parameters will be measured and analyzed by using the automatic visual inspection system that is implemented with CCD camera, optical parts, background lighting, and image processing algorithms. Finally we are able to achieve success rate above 99% to detect the welding faults of capacitors in the field test.

• Proceedings of the KWS Conference
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• v.43
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• pp.183-184
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• 2004

High capacity container carrier has been considered for many decades to transport the more containers at the same time. Therefore, it is required for high capacity container ship to be applied thicker plate to accomodate a number of containers compared to that of general container ship. To maintain the same productivity of this thicker plate, new welding process should be considered. One of the process for vertical-up position is 2 electrodes EGW(Electro Gas Welding). 2 ectrodes EGW was applied and evaluated whether it can be applicable or not. The heat input used for 72mm thick plate was 520k11cm. from the mechanical test, it is considered that this process can be applicable, showing satisfaction of mechanical properties such as tensile strength, elongation and impact property.

• Proceedings of the KWS Conference
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• 2005.11a
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• pp.150-151
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• 2005

High capacity container carrier has been considered for many decades to transport the more containers at the same time. Therefore, it is required for high capacity container ship to be applied thicker plate to accomodate a mumber of containers compared to that of general container ship. To increase productivity of welding, new welding process should be considered. A representive process for increase of weld productivity is EGW(Electrode Gas Welding) process. Both sides EGW process was evaluated for thicker-plate TMCP Steel. From the test result, it is considered that this process can be applied, showing satisfaction of mechanical properties such as tensile strength and impact property.

• Journal of Industrial Technology
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• v.27 no.A
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• pp.69-76
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• 2007

The body of an excavator, one sort of the construction equipment, consists of mainframe part, track frame part, boom part and arm part. The all parts are manufactured in the body welding operation. The scheduling in the body welding operation of a construction equipment manufacturing is to take all the various constraints into consideration. The offset time, due date, daily capacity of operations, daily jig's capacity, precedence relation, outsourcing, alternative resource and all of the shop floor environment should be considered. An APS(Advanced Planning & Scheduling) system is a proper and efficient system in such circumstance. In this paper, we present an APS system, the optimal scheduling system for the construction equipment manufacturing specifically for the body welding operation, using ILOG Solver/Scheduler. ILOG Solver/Scheduler is a general purposed commercial software which supports to find a feasible or optimal solution using object oriented technique and constraints satisfaction programming, given constraints and objectives.

• Steel and Composite Structures
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• v.34 no.3
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• pp.377-391
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• 2020

A concrete filled steel tube (CFT) column with stiffeners has preferable behavior subjected to axial loading condition due to delay local buckling of the steel wall than traditional CFT columns without stiffeners. Welding lines in welded built-up steel box columns is expected to behave as longitudinal stiffeners. This study has presented a numerical investigation into the behavior of built-up concrete filled steel tube columns under axial pressure. At first stage, a finite element model (FE) has been built to simulate the behavior of built-up CFT columns. Comparing the results of FE and test has shown that numerical model passes the desired conditions and could accurately predict the axial performance of CFT column. Also, by the raise of steel tube thickness, the load bearing capacity of columns has been increased due to higher confinement effect. Also, the raise of concrete strength with greater cross section is led to a higher load bearing capacity compared to the steel tube thickness increment. In CFT columns with greater cross section, concrete strength has a higher influence on load bearing capacity which is noticeable in columns with more welding lines.