• 한국공간구조학회논문집
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• 제11권4호
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• pp.37-47
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• 2011

재하속도에 따른 용접강관의 모멘트-곡률 거동특성에 관한 해석적 연구를 수행하였다. 3차원 열역학해석을 통하여 용접이음부의 잔류응력을 산출하였다. 그리고 동적소성모델이 적용된 탄소성 유한요소해석 프로그램을 이용하여 잔류응력을 고려한 용접강관(Welded pipe)의 동적해석을 수행하였다. 그리고 용접이음부가 없는 일반강관(Seamless pipe)에 대한 동적거동과의 비교를 통하여 해석을 수행하여 용접강관의 해석력과 해석결과는 용접강관의 모멘트가 일반강관의 모멘트에 비해 낮은 응답을 보였으나 재하속도가 증가함에 따라 모멘트 응답의 차이는 점차 감소하는 경향을 보였다.

• 한국안전학회지
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• 제17권4호
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• pp.52-60
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• 2002

Failure criterion is a parameter to represent the resistance to failure of locally wall thinned pipe, and it depends on material characteristics, defect geometry, applied loading type, and failure mode. Therefore, accurate prediction of integrity of wall thinned pipe requires a failure criterion adequately reflected the characteristics of defect shape and loading in the piping system. In the present study, the finite element analysis was performed and the results were compared with those of pipe experiment to develop a sound criterion for failure of internally wall thinned pipe subjected to combined pressure and bending loads. By comparing the predictions of failure to actual failure load and displacement, an appropriate criterion was investigated. From this investigation, it is concluded that true ultimate stress criterion is the most accurate to predict failure of wall thinned pipe under combined loads, but it is not conservative under some conditions. Engineering ultimate stress estimates the failure load and displacement reasonably for al conditions, although the predictions are less accurate compared with the results predicted by true ultimate stress criterion.

• 한국가스학회지
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• 제13권2호
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• pp.7-13
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• 2009

관망 내 배관의 간섭 거동에 따른 지하 매설 배관의 영향선 분석을 위하여 실제 환경에 부합 하도록 지하의 상부와 하부에 각각 하수관거와 가스관을 매설하여 유한요소모델을 구현하였으며, 두 배관의 교차 정도에 따라 하부 가스 배관의 영향선을 분석하였다. 하수관거와 가스관은 각각 1.0m와 3.39m의 매설심도를 가지며, 두 배관이 이루는 교차각은 $0{\sim}90^{\circ}$에 대하여 해석을 실시하였다. 본 연구에서는 Ring Deflection과 Bending Stress의 결과로부터, 교차각에 따른 영향선을 분석하였으며, 그 결과 두 배관이 이루는 교차각과 하부 배관의 영향선은 일치함을 알 수 있었다. 따라서 배관의 간섭 거동에 따른 하부 배관의 영향선은 두 배관의 교차각과 깊은 관계가 있다고 판단된다.

• Steel and Composite Structures
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• 제18권1호
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• pp.29-50
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• 2015

With a quasi-three point bending apparatus, ratcheting deformation is studied experimentally on a pressurized austenitic stainless steel Z2CND18.12N pipe under bending load and vertical displacement control, respectively. The characteristic of ratcheting behavior of straight pipe under both control methods is achieved and compared. The cyclic bending loading and internal pressure influence ratcheting behavior of pressurized straight pipe significantly under loading control and the ratcheting characteristics are also highly associated with the cyclic displacement and internal pressure under displacement control. They all affect not only the saturation of the ratcheting strain but the ratcheting strain rate. In addition, ratcheting simulation is performed by elastic-plastic finite element analysis with ANSYS in which the bilinear model, Chaboche model, Ohno-Wang model and modified Ohno-Wang model are applied. By comparison with the experimental data, it is found that the CJK model gives reasonable simulation. Ratcheting boundaries under two control modes are almost same.

• 한국산학기술학회논문지
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• 제11권10호
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• pp.4018-4023
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• 2010

합성구조에서 강재와 콘크리트 사이의 경계면에 효과적인 응력전달과 합성거동을 유도하기 위하여 스터드, 채널, 유공강판 등이 사용된다. 많은 연구자들이 여러 종류의 전단연결재의 특성을 개선시키기 위해 많은 노력을 기울이고 있다. 본 연구에서는 말뚝구조물과 확대기초와의 합성을 위해 개방형 유공강판 전단연결재로 보강된 강관 말뚝머리의 휨거동을 분석하였다. 개방형 유공강판 전단연결재로 보강된 강관말뚝의 휨거동을 규명하고, 다양한 변수해석에서 요구되는 정보를 얻고자 유한요소해석 프로그램인 ABAQUS를 사용하여 비선형 유한요소 해석을 수행하였다.

• 대한기계학회논문집A
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• 제25권11호
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• pp.1873-1880
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• 2001

The effects of restraint of pressure induced bending(PIB) on crack opening for circumferential through-wall crack in a pipe were investigated. In this study, the elastic and elastic-plastic finite element analyses were performed to evaluate crack opening displacement(COD) for various restraint conditions and crack size. The results showed the restraint of PIB decreased crack opening for a given crack size and tensile stress, and the decrease in crack opening was considerable for large crack and short restraint length. A1so, the effect was more significant in tole results of elastic-plastic analysis compared with in the elastic analysis results. In the elastic-plastic analysis results, tole restraint effect was increased with increasing applied tensile stress corresponding to internal pressure. Additionally, the restraint effect on COD was independent on the variation in pipe diameter and decreased with increasing pipe thickness, and It depended on not total restraint length but shorter restraint length for non-symmetrically restrained.

• 대한기계학회논문집A
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• 제27권1호
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• pp.8-17
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• 2003

Fracture behaviors of pipes with local wall thinning are very important for the integrity of nuclear Power Plant. In Pipes of energy Plants, sometimes, the local wall thinning may result from severe erosion-corrosion (E/C) damage. However, the effects of local wall thinning on strength and fracture behaviors of piping system were not well studied. In this paper, the monotonic bending tests were performed of full-scale carbon steel pipes with local wall thinning. A monotonic bending load was applied to straight pipe specimens by four-point loading at ambient temperature without internal pressure. From the tests, fracture behaviors and fracture strength of locally thinned pipe were manifested systematically. The observed failure modes were divided into four types; ovalization. crack initiation/growth after ovalization, local buckling and crack initiation/growth after local buckling. Also, the strength and the allowable limit of piping system with local wall thinning were evaluated.

• 대한조선학회논문집
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• 제40권2호
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• pp.63-68
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• 2003

With the trend of large-sized ship in Korea, recently several hundreds of thousands of U-bolts for a year have been used as a pipe fastener In this paper, we have evaluated the strength for present U-bolt structure by pipe supporting conditions(deck, ceiling and wall mounting type) For this purpose, the equivalent and bending stresses have been calculated by linear elastic analysis using the finite element program ABAQUS. At the same time, a variety of load conditions such as design pressure, weight effect and acceleration are also considered.

• Steel and Composite Structures
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• 제32권3호
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• pp.313-323
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• 2019

Ratcheting boundary is firstly determined by experiment, elastic-plastic finite element analysis combined with C-TDF and linear matching method, which is compared with ASME/KTA and RCC-MR. Moreover, based on elastic modulus adjustment procedure, a novel method is proposed to predict the ratcheting boundary for a pressurized pipe subjected to constant internal pressure and cyclic bending loading. Comparison of ratcheting boundary of elbow pipe determined by the proposed method, elastic-plastic finite element analysis combined with C-TDF and linear matching method, which indicates that the predicted results of the proposed method are in well agreement with those of linear matching method.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.1778-1782
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• 2007

Based on three-dimensional (3-D) FE limit analyses, this paper estimates effect of internal pressure on plastic limit loads for elbows with circumferential through-wall crack under in-plane bending incorporating large geometry change effects. Circumferential through-wall crack in extrados is considered. The FE limit analyses using the large geometry change option provide plastic collapse loads (using the twice-elastic-slope method). For the bending mode, closing bending is considered. Other relevant variables affecting plastic limit loads are systematically varied, related to pipe bend geometry (the mean radius, thickness and bend curvature) and defect geometry (the length of circumferential through-wall crack).