• 대한기계학회논문집A
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• 제28권11호
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• pp.1768-1775
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• 2004

The compressive axial collapse tests were performed to investigate collapse modes and energy absorption characteristics of Al/CFRP compound tubes which are aluminum tubes wrapped with CFRP(Carbon Fiber Reinforced Plastics) outside the aluminum circular and square tubes. Based on collapse characteristics of aluminum tubes and CFRP tubes respectively, the axial collapse tests were performed for Al/CFRP compound tubes which have different CFRP orientation angles. Test results showed that Al/CFRP compound tubes supplemented the unstable brittle failure of CFRP tubes due to ductile nature of inner aluminum tubes. In the light-weight aspect, specific energy absorption were the highest for Al/CFRP, CFRP in the middle, and aluminum the lowest. Also, specific energy absorption of circular tubes was higher than square tubes'. It turned out that CFRP orientation angle of Al/CFRP compound tubes influence specific energy absorption together with the collapse modes of the tubes.

• International Journal of Automotive Technology
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• 제6권5호
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• pp.501-506
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• 2005

With the respective collapse characteristics of aluminum and CFRP (Carbon Fiber Reinforced Plastics) tubes in mind, axial collapse tests were performed for aluminum/CFRP compound tubes, which are composed of square or circular shaped aluminum tubes wrapped with CFRP outside. In this study, the collapse modes and the energy absorption characteristics were analyzed for aluminum/CFRP compound tubes which have different fiber orientation angle of CFRP. Fracture modes in the aluminum/CFRP compound tubes were rather stable than those in the CFRP tubes alone, probably due to the ductile nature of the inner aluminum tubes. The absorbed energy per unit volume of the aluminum or the aluminum/CFRP compound tubes was higher than that of CFRP tubes. Meanwhile, the absorbed energy per unit mass, for the light-weight design aspect was higher in the aluminum/CFRP compound tubes than in the aluminum tubes or the CFRP tubes. The energy absorption turned out to be higher in circular tubes than in square tubes. Beside the collapse modes and the energy absorption characteristics were influenced by the orientation angle, and the compound tubes took the most effective energy absorption when the fiber orientation angle of CFRP was 90 degrees.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2004년도 추계학술대회 논문집
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• pp.108-113
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• 2004

The compressive axial collapse tests were performed to investigate energy absorption characteristics of Al/CFRP compound tubes which are aluminum tubes wrapped with CFRP (Carbon Fiber Reinforced Plastics) outside the aluminum circular and square tubes. Based on collapse characteristics of aluminum tubes and CFRP tubes respectively, the axial collapse tests were performed for Al/CFRP compound tubes which have different fiber orientation angles. Test results showed that Al/CFRP compound tubes supplemented the unstable brittle failure of CFRP tubes due to ductile nature of inner aluminum tubes. In the light-weight aspect, specific energy absorption were the highest for Al/CFRP, CFRP in the middle, and aluminum the lowest. Also, specific energy absorption of circular tubes was higher than square tubes'. It turned out that fiber orientation angle of Al/CFRP compound tubes influence specific energy absorption together with the collapse modes of the tubes.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.622-628
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• 2003

The purpose of this study is to evaluate the effect of local wall thinning on the collapse of elbow subjected to internal pressure and bending moment. Thus, the nonlinear 3D finite element analyses were performed to obtained collapse moment of elbow containing various wall thinning defects under two loading; modes (closing and opening modes) and defect locations (intrados and extrados). From the results of analyses, the influence of wall thinning defect on the global moment-rotation behavior of elbow was discussed, and the dependance of collapse moment of elbow on wall thinning depth, length, and circumferential angle was investigated under different loading mode and defect location.

• 대한기계학회논문집A
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• 제28권4호
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• pp.402-409
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• 2004

The purpose of this study is to investigate the effect of local wall thinning on the collapse of elbow subjected to internal pressure and bending moment. Thus, the nonlinear three-dimensional finite element analyses were performed to obtain the collapse moment of elbow containing various wall thinning defects located at intrados and extrados under two loading modes (closing and opening modes) with internal pressure. From the results of analysis, the effect of wall thinning defect on the global moment-rotation behavior of elbow was discussed, and the dependence of collapse moment of elbow on wall thinning depth, length, and circumferential angle was investigated under different loading mode and defect location.

• 한국자동차공학회논문집
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• 제2권1호
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• pp.65-72
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• 1994

Collapse characteristics of thin-walled hatted section tubes are investigated. The square section members with flanges are substituted by the equivalent rectangular tube. The stiffening effects of flanges are transformed to the restraining plate with the equivalency of buckling strength. The square tubes of single-hatted and double-hatted sections are investigated. The double-hatted section members show symmetric and antisymmetric crushing modes depending on the stiffness of flanges. The single-hatted section members show only symmetric modes. The bifurcation point of the compact crushing modes are investigated by experiments and shown almost same thickness-width ratio of the rectangular tubes. A large maximum crippling strength can be obtained by double-hatted section members with proper flange dimensions.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2005년도 추계학술발표대회 논문집
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• pp.83-86
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• 2005

The front-end side members of automobiles, such as the hat-shaped section member, absorb most of the energy during the front-end collision. The side members absorb more energy in collision if they have higher strength and stiffness, and stable folding capacity (local buckling). Using the above characteristics on energy absorption, vehicle should be designed light-weight to improve fuel combustion ratio and reduce exhaust gas. Because of their specific strength and stiffness, CFRP are currently being considered for many structural (aerospace vehicle, automobiles, trains and ships) applications due to their potential for reducing structural weight. Although CFRP members exhibit collapse modes that are significantly different from the collapse modes of metallic materials, numerous studies have shown that CFRP members can be efficient energy absorbing materials. In this study, the CFRP side members were manufactured using a uni-directional prepreg sheet of carbon/Epoxy and axial static collapse tests were performed for the members. The collapse mode and the energy absorption capability of the members were analyzed under the static load.

• 대한조선학회논문집
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• 제28권2호
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• pp.251-267
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• 1991

평면 골조 구조물로 이상화된 Web frame의 최종강도를 합리적으로 추정하기 위해 기존의 탄성해석 방법 대신에 구조물의 소성붕괴를 최종상태로 가정하여 구조해석을 수행하는 소성 해석 방법으로 선형 계획법과 Compact procedure를 정식화 하였고, 그 결과를 탄소성 해석과 비교하여 Web frame의 안전성 평가에 있어서 소성강도 해석 방법의 유용성을 검토하였다. 또한 구조해석에 사용되는 변수들의 확률적 특성을 고려하여 구조물의 안전성 평가를 하는 신뢰성 해석을 위해 소성붕괴 해석에서 얻어지는 구조물이 소성 파괴모드를 신뢰성 모델로서 사용 하였으나, 선체와 같이 과잉 구속되어 있는 부정정 구조물이 갖는 다수의 파괴모드 문제를 처리 하기 위해 기본 파괴모드 해석 방법과 자동 파괴모드 해석 방법을 이용하였고, 얻어진 파괴 모드로 부터 Web frame의 파괴확률을 계산하여 구조물의 안전성 평가에 있어서 확정론적인(deterministic)방법과 확률론적인(probabilistic)방법을 비교 검토하였다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1997년도 춘계학술대회논문집
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• pp.265-272
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• 1997

In this paper the bending collapse characteristics of 60 series Al rectangular tubes were studied with a pure bending collapse test rig which could apply the pure bending moment, there occured three kinds of bending collapse modes - local buckling, delayed buckling, tensile failure - depending on the b/t(width/thickness) ratio and material properties. Experiment results are compared with the results of finite element method.

• 한국전산구조공학회논문집
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• 제28권3호
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• pp.249-257
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• 2015

철골보통중심가새골조의 수직불균형력에 대한 설계 요구사항이 KBC2009에서 처음으로 도입하였고, 이를 통하여 설계지진에서의 인명안전성능이라는 목표내진성능을 만족하도록 유도하고 있다. 그러나 수직 불균형력의 영향이 ASCE7-10에서 암시적으로 제시하는 최대고려지진에서의 구조물 붕괴방지성능에 미치는 영향에 대한 연구는 매우 제한적으로 이루어지고 있어 KBC2009를 따라 설계된 철골보통중심가새골조의 붕괴성능을 조사할 필요가 있다. 이를 위하여 본 논문에서는 역V형 철골보통중심가새골조의 최대고려지진에서의 붕괴양상을 조사하였다. 두 가지 지반조건과 세 가지 다른 수직불균형력 조건을 해석변수로 하여 총 6개의 5층 규모의 철골보통중심가새골조 표본건물을 설계하였다. 비선형 정적해석과 비선형 동적해석을 통하여 표본건물들의 내진성능과 붕괴양상을 조사하였다. 해석결과를 통해 수직 불균형력은 철골보통중심가새골조의 내진성능에 지대한 영향을 미쳤고, 바람직한 붕괴양상과 붕괴방지성능을 달성하기 위하여 불균형력에 대한 적절한 고려가 필요한 것으로 나타났다.