• The Korean Journal of Rheology
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• v.7 no.2
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• pp.128-138
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• 1995

본 논문에서는 전단띠형성에 있어서 전단변형의 집중화 현상을 이방성 탄소성 재료 에 대해서 해석하였고 소성스핀과 비등방성이 전단띠 형성에 미치는 영향을 연구하였다. 평 면응력 상태에서 소성스핀을 갖고있는 이방성 탄-소성 재료에 대해서 재료 분랑ㄴ정 해서 을 수행하여 변형률 집중화의 시작에 미치는 소성스핀과 비등방성의 효과를 연구하였다. 해 석 결과 이방성 재료에서의 전단띠 형성은 압축 또는 인장의 하중 형태나 이방성 축의 초기 각도 그리고 소성스핀의크기에 따라 그 시작이 촉진되거나 지연되었고 전단띠 생성의 방향 도 달라졌다.

• Journal of Korean Society of Steel Construction
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• v.10 no.3 s.36
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• pp.327-338
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• 1998

This paper presents the elastic behavior for panel zone and flange of connection in steel frame pier. The results of stress distributions on a series of experiments and FEM analysis models are reported herein. The investigations show that the shear stresses in the panel zone are varied with sectional-area ratio$(A_f/A_w)$ and also indicate that the nomal stresses in the flange due to the shea lag are significantly higher than the current design procedure. Based on the results, some new proposals considering the design parameters affecting connecting behavior are presented for the evaluations of stresses of panel zone and flange in connection.

• Journal of Korean Society of Steel Construction
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• v.16 no.5 s.72
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• pp.505-517
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• 2004

This paper presented equations on the stress evaluation of steel frame pier connections that were composed of a box beam and a circular column. The existing equations, which transformed the circular column into an equivalent box column had some problems; they underestimated a shear lag stress as the joint angle decreased, and overestimated a shear stress as the joint angel increased. Therefore, FE analyses were performed with various parameters, such as joint angle(${\alpha}$), span length-width ratio(L/B), and circular column-to-box beam stiffness ratio(${\alpha}$), and new equations on stress evaluation were proposed based on FE analyses. Furthermore, material and geometric nonlinear analyses were performed to estimate ultimate strength and to confirm the validity of the proposed equations.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2010.04a
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• pp.10-13
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• 2010

세그먼트 자중 등에 의한 휨모멘트와 케이블 수직압축력에 의한 합성응력이 발생되고 바닥판 경간비가 변하는 사장교의 시공단계에서는 전단지연의 영향범위가 다를 수 있다. 이 연구에서는 1면 케이블 콘크리트 박스 사장교를 대상으로 시공단계시 보강형에 고려되어야 할 합성응력에 의한 유효플랜지폭을 분석하였다. 그 결과 바닥판 경간비가 0.38 이하의 범위에서 보강형의 전폭을 유효플랜지폭으로 적용할 수 있는 것으로 해석되었다. 따라서 시공단계시 변화되는 바닥판 경간비의 크기에 관계없이 전폭을 유효플랜지폭으로 반영하는 실무관행은 안전측 설계가 되지 못할 수 가 있다. 바닥판 경간비가 작아짐에 따라서는 전폭과 캔틸레버 구조계로 유효플랜지폭을 결정하는 것이 타당하다. 이 연구에서는 수직력에 대한 도로교설계기준의 유효플랜지폭 규정에 대한 평가도 수행하였다.

• The Korean Journal of Rheology
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• v.11 no.2
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• pp.73-81
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• 1999

The intention of this research is to give criteria of designing devices using ER fluids and MR fluids. The Properties of commercial ER fluids and MR fluids are compared using a rotational viscometer. The yield strength is compared upon changes of shear rate, temperature and applied fields. MR fluids seem less sensitive to temperature change than ER fluids. In cases of MR and ER fluid dampers, the time delay and damping force are measured in tension and compression mode when the applied field changes.

• Journal of Korean Society of Steel Construction
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• v.14 no.3
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• pp.433-441
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• 2002

This study present the stressdistribution of circular column-box beam connection in steel piers. Experiments were carried out for hollow and concrete filled connections, depending on the joint angle. To determine vertical and shear stress distribution, this study examined the equivalent web depth dc' that is mainly used in existing design equation. Lidewise, as additional equivalent web depth was introduced. Stress values that were calculated using equivalent wev depth were also compared with the test stress value. Results showed that stresses of hollow and filled connections have great differences. However, dc' has a limitation for some joint angles. Likewise, stress of filled connection was less than that of the hollow connection. The test value of filled connection was also compared with design equations that were introduced from the hollow connection.

• 한국도로학회:학술대회논문집
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• 2004.10a
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• pp.235-238
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• 2004

• Journal of the Computational Structural Engineering Institute of Korea
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• v.23 no.4
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• pp.343-351
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• 2010

Bending and axial compressive stresses are distributed across the whole upper flange of a box girder bridge which has the span-to-depth ratio (B/L) of below 0.5, according to Korea Bridge Design Specifications (Minister of Land, Transport and Maritime Affairs, 2005). Shear lag phenomenon, however, can take place in the construction phase of cable-stayed bridge, in which stresses combining bending moment due to dead weight and cable vertical compression are induced. This study aims to analyze the effective width of flange over which composite stresses are given, which should be calculated during the construction phase of stiffening girder of single plane cable-stayed box girder bridge. The study results indicate that the full width of stiffening girder can be regarded as the effective flange width when the span-to-depth ratio for the deck is below 0.38. In other words, the area, where shear lag is taken into consideration, is larger than the width of box girder in single plane cable-stayed box girder bridges. Therefore, the current practice of considering the full width as the effective flange width regardless of changes of the span-to-depth ratio during the construction stage can produce an unsafe bridge. If the effective flange width is determined according to the single span structural system in the early stage of construction when the span-to depth ratio for the deck is high and composite stresses of every part expect each end of the bridge are calculated, it can result in a safe structural design. Since the span-to-depth ratio gradually decreases, however, it is appropriate to determine the effective width of flange on the basis of the full width and the cantilever structural system.

• Journal of the Korean Society of Marine Environment & Safety
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• v.12 no.1 s.24
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• pp.9-14
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• 2006

Analysis has been made of the anti-corrosive property of organic coating under the shear stress of the flow by means of AC impedance method. Marine anti-corrosive painted panels were placed in the water channel with varying flow rate, thereby experiencing varying flow shear stress on the surfaces. The velocities of the salt water were ranged from 1.48 to 5.2 m/s and the coating thickness of from $70{\mu}m\;to\;140{\mu}m$. For all coating thicknesses investigated, the poorer anti-corrosive property and the lower adhesion strength have been found for the higher shear stress. It has been found that the shear stress accelerates the aging of organic marine coatings.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.12 no.4
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• pp.63-69
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• 2003

In discontinuous composite mechanics, shear lag theory is one of the most popular model because of its simplicity and accuracy. However, it does not provide sufficiently accurate strengthening predictions in elastic regime then the fiber aspect ratio is small. This is due to its neglect of stress transfer across the fiber ends and the stress concentrations that exist in the matrix regions near the fiber ends. To overcome this shortcoming, a more simplified shear lag model introducing the stress concentration factor which is a function of several variables, such as the modulus ratio, the fiber volume fraction, the fiber aspect ratio, is proposed. It is found that the modulus ratio($E_f$/$E_m$) is the essential variable among them. Thus, the stress concentration factor is expressed as a function of modulus ratio in the derivation. It is found that the proposed model gives a good agreement with finite element results and has the capability to correctly predict the values of interfacial shear stresses and local stress variations in the small fiber aspect ratio regime.