• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.847-850
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• 2008

In simply supported concrete beams with concentrated load, there is arch action that the internal lever arm length varies through shear span. Recently shear analysis model considering this effect has been developed, but the analysis algorithm is so complicated. Moreover, the variation of internal lever arm length is not considered on the shear compatibility condition. In this study, the shear analysis model is developed more simply and the variation of internal lever arm length is considered on the shear compatibility condition. From these modifications, an actual shear behavior of RC beams subjected to concentrated load could be expected from the results of the proposed analysis model.

• Journal of the Korea Concrete Institute
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• v.15 no.3
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• pp.454-461
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• 2003

This study addressed a procedure to carry out an experimental study on a behavior of simple and continuous concrete beams. For this purpose, sample concrete beams were fabricated and sensors for the measurement of strains and deflections were attached both on the surface of the beams and inside them. Two types of sensors were used to measure strains associated with loading: electric resistance strain sensors and fiber optic sensors. Displacement gauges were also attached on the bottoms of beams to investigate the behavior of beams more rationally. The behavior of the beams was then evaluated throughout the results measured from different sensors while they were subject to steady loading up to failure. From results of this study, it was found that concurrent use of sensors and displacement gauges is helpful in investigating the behavior of concrete beams more effectively. Especially, combined-type strain sensors specifically fabricated in this experiment were found not to be affected by the occurrence of cracks so significantly and to be very effective in monitoring strains of concrete structure. It was also observed that beams show nonlinear force-displacement relationship and reinforcing bars take charge of resisting the external force once cracks occur in concrete beams.

• Proceedings of the Korean Nuclear Society Conference
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• 1995.05b
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• pp.675-680
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• 1995

원자로 압력용기 재료인 SA508-3 강의 인장소성변형에 따른 자기적 성질변화를 연구하였다. 소성변형에 따른 보자력, 잔류자화, 자기이력손실 및 Barkhausen Noise의 변화를 측정하였으며, 변형에 따른 자기적성질의 변화를 자구와 전위와의 상호작용으로 설명하였다. 강자성체의 자기적 성질과 기계적 성질 사이는 밀접한 관련이 있으며, 이를 이용하면 압력용기강의 조사효과 평가에 적용 할 수 있을 것으로 보인다.

• Journal of KSNVE
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• v.21 no.3
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• pp.32-35
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• 2011

자기변형(magnetostriction)에 관한 연재물 2번째로 이번 호에서는 자기변형 현상을 보이는 각종 물질에 대해서 알아보기로 한다. 편의상 별도의 합금을 만드는 과정을 거치지 않아도 자연계에서 얻을 수 있는 비희토류계 물질과 특별한 공정을 통해서만 만들어낼 수 있는 희토류계 물질로 나누었다. 자기변형 현상에 대한 물리적인 이해는 3번째 연재물부터 진행할 것을 밝힌다.

• Journal of the Korean Wood Science and Technology
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• v.23 no.4
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• pp.10-17
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• 1995

본 연구는 화염에 노출된 목재 부재의 거동에 관련된 자료를 얻기 위해 수행되었다. 목재 보에 대한 현행 내화 모델들은 외곽부 섬유의 MOE나 휨강도의 감소, 그리고 화염노출의 계속으로 인한 단면의 감소 등에 기초하고 있다. 하지만 이런 모델들은 정확한 거동 예측이 힘들다. 따라서 목재 보의 거동을 정확히 예측하기 위해 본 연구에서는 변형 단면을 이용한 내화거동 모델을 개발하고자 하였다. 이 변형 단면모델을 개발하기 위하여 온도분포 온도와 목재의 물리적 성질간의 상관관계를 이용하였다. 본 연구를 통해 온도와 목재의 휨성질간의 정확한 관계가 제공되기만 한다면 본 방법이 화염에 노출된 목재 보의 변형을 잘 예측할 수 있음을 알 수 있었다.

• Journal of the Society of Naval Architects of Korea
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• v.33 no.1
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• pp.206-213
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• 1996

Longitudinal deformation due to welding of built-up beams must be straightened for attachment with plates. Straightening of deformation is carried out by much experienced workers and requires much time and labor. In this study, a procedure to calculate the required reverse curvatures to straighten the welding deformation is presented and a method to simulate the fabrication procedures for the built-up beams is developed for the purpose of improvement of productivity.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.20 no.6
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• pp.719-730
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• 2007

This study presents a thin-walled space frame element based on the classical Timoshenko beam theory. The element is derived according to the assumed strain field in order to resolve the shear-locking phenomenon. The shape function is developed in accordance with the strain field which is assumed to be constant at a 2-noded straight frame element. In this study, the geometrically nonlinear analysis applies the Corotational procedure in order to evaluate unbalanced loads. The bowing effect is also considered faithfully. Two numerical examples are given; monosymmetric curved and nonsymmetric straight cantilever. When these example structures behave lateral-torsional bucking, the critical loads are obtained by this study and ABAQUS shell elements. Also, the post-buckling behavior is examined. The results give good agreement between this study and ABAQUS shell.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2005.03a
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• pp.220-227
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• 2005

최근에 수행된 철골모멘트 접합부의 실험 및 해석결과에 의하면, 기둥으로 각형강관을 가진 접합부가 H형강을 기둥으로 사용하는 접합부에 실험체에 비해서 조기에 스캘럽 단부에서 취성파단이 발생하는 열등한 변형능력을 나타냈다. 이는 각형강관 기둥의 면외변형에 따른 보 웨브의 모멘트 전달효율의 저하, 스캘럽이 가지는 노치효과 및 합성보의 구속효과가 주요원인으로 밝혀졌다. 실험결과는 또한 개선된 수평스티프너로 하부 플랜지를 보강한 실험체는 우수한 변형능력을 가짐을 보였다. 본 연구에서는 이러한 영향을 고려하여, 다양한 수평스티프너로 보강된 접합부에 관한 유한요소해석을 실시하였다. 해석결과를 바탕으로 파일럿 테스트를 실시한 결과, 수평스티프너로 보강된 RBS 접합부 (SR)와 연장된 수평스티프너를 가진 접합부(LH)는 우수한 변형능력을 보였다.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.193-196
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• 2008

This paper proposes a method to predict the ductility capacity of reinforced concrete beam-column joints failing in shear after the formations of plastic hinges at both ends of the adjacent beams. The current design code divides joints into two categories: Type 1 for structures in non seismically hazard area and Type 2 in seismically hazard area. While there are many researches related to joint shear strength in Type 1, those in regard to joint ductility capacity of Type 2 are scarce. This paper classified the ductility capacity of beam-column joints into column, joint panel, and beam deformability. Since a brittle failure such as shear or bond failure in the columns must be avoided, column deformability was calculated by elastic analysis. The plastic hinges of the adjacent beams affect joint deformability. Therefore, the prediction of joint deformability was calculated with consideration to the degradation of the diagonally compressed concrete due to the strain penetration.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.5
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• pp.396-404
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• 2015

The UAV's wing has high aspect ratio that is suitable for the high altitude and long endurance. Knowing the real-time deformation of wing structure in flight, it can be utilized in structural health and loading status monitoring, improvement of control effectiveness and extraordinary vibration phenomena using displacement-strain relationship. In this paper, nonlinear displacement prediction algorithm was developed for prediction of large structural deflection in flight. The algorithm was validated through the comparison with finite element analysis results and also experimental results for several large tip displacements of cantilever beam. The predicted displacements using strains are agreed well with the measured values from laser displacement sensor.