• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2001년도 춘계학술발표대회 개요집
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• pp.71-74
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• 2001

• 한국추진공학회지
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• 제11권3호
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• pp.7-12
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• 2007

마찰용접은 소재를 서로 마찰시켜 마찰열에 의해 용접하는 방법이다. 본 연구는 내부에 유동부를 갖는 부분을 마찰용접을 이용하여 용접했을 때 유체의 유동에 영향이 없는 유동부를 설계하는데 목적을 두고 있다. 용접부의 설계 변수를 결정하고 이에 대하여 마찰용접 해석을 DEFORM-2D를 이용하여 해석을 수행하였다. 마찰용접 해석을 수행하기 위해 온도변화에 따른 마찰계수와 업셋 압력, 소재의 분당회전수, 그리고 유동응력을 입력해 주었다. 해석결과에 따라서 유동에 영향이 없는 용접부의 최적형상을 결정하였다.

• Journal of Welding and Joining
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• 제27권5호
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• pp.34-41
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• 2009

Thermal and mechanical characteristics in dissimilar SS400-STS304 steel weldment have been investigated by 3D thermal elastic-plastic analysis. Moreover, the influence of welding residual stresses on the mechanical behaviour of this welded joint, by applying superimposed external load (tension load) was determined. The residual stresses obtained by numerical simulation were compared with the experimentally measured results. The FE results were in good agreement with the measured values. The mechanical test (hardness, tensile test) and metallurgical analysis was carried out to ensure the weld integrity. Hence, possibility of applying SS400-STS304 dissimilar steels in industries has been established.

• Journal of Welding and Joining
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• 제30권5호
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• pp.57-63
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• 2012

The purpose of this study is to evaluate the welding distortion of the circular type lap joint in STS304L of 0.7mm thickness by using FEA. In order to do it, a heat input model for GTA welding process with non-consumable electrode was established through comparing the molten pool shapes and temperature distributions obtained by both FEA and experiment. With the heat input model, the welding distortion of the circular type lap joint was evaluated by 3-D FEA. From FEA results, it was found that 3-D FEA with proper heat input model can be used for the evaluation of the excessive distortion of the circular type lap joint of STS304L thin plate. In addition, the root cause of the excessive distortion in the weld was also identified as the excessive compressive residual stress in the tangential direction of the weld.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2000년도 가을 학술발표회논문집
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• pp.11-17
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• 2000

,An residual stress and out-of plane deformation produced by butt welding was analyzed by four kinds of 3D-FEM programs(Thermal El-P1 Analysis) developed by authors. The magnitude of deformation of perpendicular to the welding line generated by butt welding was large when the reduced integration method was used. This was because of removal of the locking phenomenon, which it was generally known that the stiffness of the shear component of out-of-plane was largely evaluated. And the magnitude of residual stress was analyzed by using the FEM program based on a large and small deformation theory was similar to that was analyzed by the redeced integration method.

• Journal of Welding and Joining
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• 제18권3호
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• pp.76-82
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• 2000

In this study, three-dimensional heat flow in laser beam welding for deep penetration was analyzed by using F.E.M common code, and then the results were compared with the experimental data. The models for analysis are full penetration welds and are made at three different laser powers (6, 9.9, 4.5 kW) with two different welding speeds (5.8mm/s, 5mm/s). The characteristics of thermal absorption by the workpiece during deep penetration laser welding can be represented by a combination of line heat source through the workpiece and distributed heat source at the top surface due to the plasma plume above the top surface. This gives an insight into the way in which the beam interacts with the material being welded. The analyses performed with the combined heat source models show comparatively good agreement between the experimental and calculated melt temperature isotherm, i.e, the fusion zone boundary. The results are used to explain the "nail head" appearance of fusion zone, which is quite common in laser beam welds.eam welds.

• 대한기계학회논문집
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• 제7권3호
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• pp.313-318
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• 1983

It is required in designing a spot welding to get in advance an estimated figure of nugget diameter. A method of estimating nugget diameter of low carbon steel sheets is suggested in tesms of utilizing elastic calculation in theory and of making a sectional observation of specimen of spot welding in experiment. The resultant findings are summarized as follows: 1) A contact diameter of sheet, 2.gamma.$_{o}$=d sub e/+(1.1)t, wheer de is the electrode tip diameter and t is the thickness of sheets. 2) The practical measurement of the nugget diameter reveals that $d_{n}$=(1.05) $d_{e}$+(0.9)t, and $d_{b}$ is less by 0.8-4.3% than 2.gamma.$_{o}$. 3) The more $d_{n}$ is as compared with t, the less the difference between a theoretical value and an experimental value is. 4) In the spot welding of thin steel sheets less than 3mm in thickness that are commonly used in sheet metal works, the contact diameter equals the nugget diameter. In this case, either the theoretical or experimental approach can be used for estimating the nugget diameter.meter.ter.r.

• Journal of Welding and Joining
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• 제9권3호
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• pp.34-40
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• 1991

An automatic welding system was constructed with a personal computer to capture the welding data in addition to vision seam tracking for the gas metal arc welding process. The monitoring of welding signals is composed of the acquisition of welding voltage and current, obtained by using two differential amplifiers and A/D converters, and processing of the measured data. Using interrupt handing circuit for time sharing, two jobs of seam tracking and monitoring were performed at the required sampling time. Relations between welding signals and various welding circumstances were analyzed from the experimental results.

• International Journal of Korean Welding Society
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• 제3권1호
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• pp.45-50
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• 2003

Welding using lasers can be mass-produced in high speed. In the laser welding, performing real-time monitoring system of the welding quality is very important in enhancing the efficiency of welding. In this study, the plasma and molten metal which are generated during laser welding were measured using the UV sensor and IR sensors. The results of laser welding were classified into five categories such as optimal heat input, little low heat input, low heat input, partial joining due to gap mismatch, and nozzle deviation. Also, a system was formulated which uses the measured signals with a fuzzy pattern recognition method which is used to perform real-time evaluation of the welding quality and the defects which can occur in laser welding.

• 제어로봇시스템학회논문지
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• 제20권7호
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• pp.760-766
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• 2014

This paper represents a portable robot for use in the welding process of the double hulls in shipbuilding yards. It has 5 degrees of freedom and 3kg of payload. Its body weight is 17.3 [kg] so that human workers can carry it by hand to the work place. Its body is mainly made of magnesium and aluminum alloys. Since the robot is placed about 25m apart from its controller, EtherCAT is adopted for reliable connection between the robot and controller through a single light cable. RTX real-time kernel and KPA EtherCAT master are used to control the robot on a Windows XP environment. The performance of the developed robot is satisfactory to the requirement in welding tasks of U-type cells in shipbuilding yards.