• Proceedings of the KWS Conference
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• 1999.05a
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• pp.183-188
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• 1999

• Proceedings of the KWS Conference
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• 1999.05a
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• pp.250-252
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• 1999

• Journal of Korean Society of Steel Construction
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• v.10 no.4 s.37
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• pp.709-720
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• 1998

In order to study the distribution of welding residual stress through the plate thickness. experiment and analysis of fillet welding details were carried out. Especially, a residual stress in the weld root part of T-joint fillet weld whose measurement was difficult up to now was measured. By using the heat input and the number of the weld layers as parameters, the distribution of the 3-dimensional residual stress was investigated. As a result, we can say that with increasing the heat input, the residual stress in the weld toe and weld root barely changes. But, the area of the tensile residual stress became wide. Then, comparing a single pass with multi-pass weld method, it was found that the residual stress decreased more in multi-pass than in single pass. Moreover, it was found the thing that the area of tensile residual stress by multi-pass is lower than that by single-pass in the near weld part.

• Proceedings of the KWS Conference
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• 2010.05a
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• pp.56-56
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• 2010

최근 강구조물의 건설이 지속적으로 증가되어 왔다. 또한 강구조물의 유지관리 및 안전성에 대한 관심이 급증하고 있다. 시설물의 안전성 확보는 대형사고의 사전 예방, 공용 중 갑작스런 가동 중지에 의하여 발생되는 비용증가를 사전에 차단 할 수 있다는 점에서 그 중요성은 매우 크다고 할 수 있다. 또한 각종 구조물은 열악한 사용조건, 고온, 고압, 고속, 대형화됨에 따라 일단 사고가 발생 했을 경우 대형사고의 위험이 예상되므로, 제작시 검사의 강화뿐만이 아니라 공용 중 구조물의 안전성을 진단 할 수 있는 모니터링 체계의 확립이 필요한 시점이다. 현재 국내에서 강구조물들의 균열 모니터링 시스템에 관한 연구는 매우 미흡한 실정이며, 현재 사용되고 있는 비파괴검사 방법은 UT와 RT등이다. 이러한 방법들은 많은 시간과 경비가 소요되며 또한 거대구조물 혹은 사람의 접근이 어려운 곳에는 적용하기가 힘들다. 또한 주기적인 검사 작업으로 인한 막대한 시간과 비용의 손실이 발생되고 있으며 초기 결함을 조기에 인지하지 못함으로써 적절한 보수 보강 대책이 이루어지지 않아 보수 보강 비용의 증대를 초래한다. 더욱이, 결함이 진전된 이후에도 이것을 인지하지 못하여 적절한 대응을 하지 않는다면 대형사고로 이어질 수도 있다. 따라서 강구조물에 대한 효율적인 유지관리가 가능하고, 초기결함으로부터 균열이 진전하여 붕괴되는 사고를 미연에 방지하며 초기에 보수보강 작업을 수행함으로써 보수보강 비용도 절감 할 수 있는 모니터링 시스템의 개발이 요구되고 있다. 이러한 모니터링 시스템의 개발은 기술적 측면에서 강구조물의 효율적인 유지 관리 노하우를 얻을 수 있으며 경제 산업적 측면에서는 보수 보강 비용 및 불필요한 주기적 점검 비용을 절감 할 수 있다. 이 연구에서는 전위차법을 이용하여 강구조물의 필렛 용접부에서의 균열진전양상을 파악하고 정량화를 통해 필렛용접부의 잔여수명을 예측하였다.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.6
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• pp.1065-1070
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• 2017

Magnetic gears are magnetically coupled to the input side and the output side of the rotary machine to transmit power without mechanical contact. The magnetic gear consists of an inner rotor, an outer rotor and pole pieces. Torque ripple occurs due to the difference in reluctance between the two rotors and the pole pieces during power transmission. Torque ripple is a cause of the noise and vibration of the rotary machine, so it is necessary to minimize it. In this paper, we propose a shape that cuts the corner of the pole piece and apply a fillet to reduce torque ripple. We used a two-dimensional finite element analysis method to compare and analyze the torque ripple of the magnetic gears according to the change of the fillet parameters and to find the pole piece shape with excellent torque ripple.

• Journal of the Korean Society for Railway
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• v.14 no.2
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• pp.94-99
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• 2011

In this study, the stress reduction effect was evaluated for GFRP/Mg single lap bonded joints according to six different adherend shapes. Six different types of the single lap joint specimen were modeled and assessed using geometrically nonlinear finite element analysis. Moreover, three dimensional effect of stress distribution for the different adherend shapes was investigated. From the analysis, the dissimilar single lap bonded joint with the normal tapering and without the spew fillet (model 2) showed the highest stress values. In contrast, the peel stress values of both the square ended adherends with the spew fillet (model 3) and the reverse tapered adherends with the spew fillet (model 5) were 65.8% and 65.5% lower than the reference model.

• Journal of the Korean Society for Nondestructive Testing
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• v.23 no.3
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• pp.220-226
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• 2003

This paper presents the result of an investigation on the application of the acoustic emission method to the monitoring of fatigue crack initiation, growth and track location in welded joints. Fatigue test was carried out for a typical fillet welded joint of ship structure. AE parameter such as ring down count was analyzed in time domain and crack locations were examined by source location and cluster option which is one of the functions of AE signal processor The usability of AE mettled was confirmed for the detection of the initiation and location of through crack.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.11
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• pp.1139-1145
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• 2011

An automated anastomotic ring-pin system consisting of both the anastomotic ring-pin system and the coupler device has eliminated the drawbacks of the suture method. High density polyethylene (HDPE), a material with outstanding biocompatibility and injection molding capability, was used in the ring. SUS316 stainless steel, Ti-6Al-4Nb, Ti-6Al-4V, and unalloyed titanium were used in FEM simulations of the micropin. The authors categorized the microvascular anastomotic ring micropins into short neck (SN) and long neck (LN) groups in order to evaluate the effect of the micropin's fillet radius and neck length on the von Mises stress. The micropins were further divided into those with and without fillet. On the basis of the fillet radius rate (FRR), which represents the rate of change in the von Mises stress with respect to the availability and shape of the fillet, and the neck length rate (NLR), which represents the rate of change in the von Mises stress with respect to changes in the length of the neck within the fillet shape, it can be concluded that the SN-3 neck design is the most stable.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.29 no.3
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• pp.145-151
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• 2023

In order to extend shelf life for rockfish fillets by modified atmosphere packaging (MAP), different package atmospheres were compared in the product quality preservation. Firstly, CO₂ solubility was measured at 0, 5, 10, and 15℃ to be incorporated into the mathematical model to predict the volume and CO₂ concentration of the package at expected storage temperature. The CO₂ solubility given in Henry's constant decreased with temperature to be fitted with a linear equation. Then air packaging as control and four MAP conditions of 100 g fillets were prepared and stored for duration of 5 days at 10℃ to compare them in the quality preservation effect. Four MAP conditions employed were CO₂(60):O₂(30):N₂(10), CO₂(60):O₂(0):N₂(40), CO₂(30):O₂(30):N₂(40) andCO₂(30):O₂(0):N₂(70). MAP conditions with high CO₂ concentration inhibited total aerobic bacteria, and the conditions containing O₂ led to low TVB-N. MAP of CO₂(60):O₂(30):N₂(10) was found to be the best condition for rockfish fillet preservation considering total aerobic bacteria growth and nitrogenous volatiles production.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.445-446
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• 2010