• 대한기계학회논문집A
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• 제35권10호
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• pp.1179-1185
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• 2011

용접이음부의 신뢰성 확보는 구조물의 건전성과 내구성에 직접적인 영향을 미치기 때문에 점용접 이음재의 피로설계기준(fatigue design criterion)을 정하기 위해서는 정확한 응력해석과 체계적인 피로강도평가가 필요하다. 따라서 본 연구에서는 실제 전동차량 차체에 많이 적용되는 냉간 및 열간압연강판인 SPCC, SPCE, SPHE을 대상으로 기하학적 인자(geometrical factors)들을 선별해서 TS형과 CT형의 대표적인 점용접 이음재 시험편을 기본모델로 하여 인장전단하중을 가하여 피로강도 및 피로특성을 평가하고자 하였다. 그리고 피로균열의 발생과 성장 기구에 대한 영향을 분석하기위해 용접 시 발생되는 여러 가지 주요인자들 중 입열량에 의해 발생할 수 있는 용접잔류응력을 X-ray 회절법에 의해 실험적으로 해석하였다. 그리고 이러한 해석을 통하여 얻어진 결과를 중첩(superposition)함으로 해서 잔류응력을 고려했을 경우 너깃 단 최대주응력으로 피로강도를 재평가하여 합리적인 피로설계기준(fatigue design criterion)을 재정립하고자 하였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.950-955
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• 2005

This paper describes an intelligent filler wire feeding device which can control 3- dimensional seam tracking and the filler wire speed by measuring the gap position and the joint gap width in laser welding. By means of visual sensor controlled filling the missing material into the joint gap and 3 dimensional seam tracking, lineup errors from manufacturing tolerances and the repeatability of lineup jigs and weld robot can be balanced and at an even seam quality which avoids weld defects. In this paper, we assessed weld quality in 2mm sheets of A16061 which had various gap width by using the intelligent filler wire feeding device.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.860-864
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• 2004

This article discusses the use of pulse-echo ultrasonic testing for the stress analysis of adhesive bonds between metal sheets. The method is based on the measurement of the reflection wave at the metal/adhesive interface. After describing briefly the physical aspects of the phenomenon, an index is defined to detect defective zone of the joint(both for the lack of adhesive and for insufficient adhesion); the influence of the experimental variables(variables stress...) on the measurement is discussed. By means of a control experiment it is shown that Stress Variation in Adhesive Joints are separate to be distingguished. In this paper, Quantitative Nondestructive Evaluation in Adhesive Joints are together with Ultrasonic Testing and Finite Element Method.

• Journal of Welding and Joining
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• 제33권3호
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• pp.75-80
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• 2015

Self-piercing riveting is an joining method of advanced high strength steels (AHSS) and other dissimilar materials. It has attracted considerable interest from the automotive industry. The SPR has become an interesting alternative joining technique for difficult to weld materials such as steels and aluminium alloys. In this paper, self-piercing rivet and anvil for SPR were designed for the joining conditions with AHSS and aluminium alloy. Various conditions of SPR were simulated for the design of rivets and anvils. The simulated results were in good agreement with experimental ones. As a result, over HV500 rivet is desirable to joint SPFC780 AHSS and aluminum alloy.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.726-730
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• 1997

One approach to testing the suitability of an adhesive joint for a particular application is to build and test to destruction a representativc, sample of the joini. The noncdestructive test will not measure strength directly but will measure a parameter which can be correlated to strength. It is thercforc, essential that a suitable nondestructive rest is chosen and that its results are correctly intcrpreted. In this paper, typical Ultrasonic Signal Analysis in adhesive joints are cvaluatcci together with Interface Stress from the result of Finite Elenlent Method.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 춘계학술발표회 논문집(I)
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• pp.106-109
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• 2006

It has been shown that many reinforced concrete(RC) structures designed without seismic details have experienced brittle shear failures in the beam-column joint area and may result in large permanent deformations and structural collapse. In this study, experimental investigations for RC beam-column joints strengthened with the carbon fiber-reinforced polymer(CFRP) under cyclic loadings were presented. The use of CFRP in the joint was varied to determine the effective way of improving the structural performances of RC joints. Ten RC beam-column joints were designed and tested with cyclic loadings. The experimental results showed that the use of CFRP in RC joints would be very effective solutions to improve the seismic performances of the non-seismic RC joints. All of the non-seismic design specimens strengthened with CFRP sheets showed the significant increase of strength and ductility.

• 한국레이저가공학회지
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• 제11권3호
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• pp.16-20
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• 2008

The lap Joint welding of 6K21 aluminum sheets by Nd:YAG laser were performed with an aluminum 5183 filler wire or without a filler wire. The porosity of laser welding beads were observed through an optical microscope and X-ray photography with various levels of welding speed and gap size. The porosity was observed in the gap between upper and lower sheet near a heat affected zone when autogenous welding. Decrease of welding speed and use of AA5183 filler wire reduced porosity significantly.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2010년도 춘계학술발표대회 초록집
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• pp.96-96
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• 2010

Magnesium alloy is being used for structural material since it has high specific strength. Tubular shape was effective way for enhanced structural design. To manufacture the tube, it is necessary to weld the butted joint of both tubular formed sides. But the magnesium alloy was hardly welded with conventional welding processes. The laser welding was effective way to joint magnesium alloys because it had high weld strength and productivity compare with other welding processes. In this study, magnesium alloy sheets was formed at elevated temperature to tubular shape and welded with laser. Consequently, the magnesium alloy tube was making successful with warm forming and laser welding and bicycle frame was making with it.

• 동력기계공학회지
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• 제5권1호
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• pp.80-88
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• 2001

The spot welding method has been used in the joining of structures, automotive body, railway carriage, aircraft, household electric appliances, precision parts etc., because of brief working, easy automation, available mass production, and convenience. In this paper, the effects of welding conditions on the fatigue life and the prediction of fatigue life based on fracture mechanics theory of spot welded joint were investigated. Fatigue tests were conducted with the tensile-shear specimens welded in the various current using cold rolled steel sheets. Fatigue life of spot welded joint was predicted and compared with experimental results. Using FEM(finite element method), we analysed the distribution of stress and the condition of deformation on the environments of nugget.

• 한국디지털건축인테리어학회논문집
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• 제8권1호
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• pp.57-64
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• 2008

There are many problems in present truss-deck slab system for example welding defect, segregation, water leakage, rust and tarnish etc. These problems may be caused by spot welding thin galvanized steel plate and lattice bar. The TOX Joining Systems is to join metal sheets of different material and thickness with and without coating or painting without adding heat or a joining part. Newly developed TOX-deck slab system using non-welding joint is free from above mentioned problems. The objects of this study are suggestion of design strength of TOX joint by experimental and statistical analyses and development of window based program to design the TOX-deck slab system.