• Title/Summary/Keyword: 좌굴평가

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Buckling Analysis of Box-typed Structures using Adaptive Shell Finite Elements (적응적 쉘유한요소를 이용한 박스형 구조물의 좌굴해석)

  • Song, Myung-Kwan;Kim, Sun-Hoon
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.20 no.3
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    • pp.265-272
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    • 2007
  • The finite element linear buckling analysis of folded plate structures using adaptive h-refinement methods is presented in this paper. The variable-node flat shell element used in this study possesses the drilling D.O.F. which, in addition to improvement of the element behavior, permits an easy connection to other elements with six degrees of freedom per node. The Box-typed structures can be analyzed using these developed flat shell elements. By introducing the variable-node elements some difficulties associated with connecting the different layer patterns, which are common in the adaptive h-refinement on quadrilateral mesh, can be overcome. To obtain better stress field for the error estimation, the super-convergent patch recovery is used. The convergent buckling modes and the critical loads associated with these modes can be obtained.

Critical Buckling Characteristics of Micropiles Under Axial Loads (축하중을 고려한 마이크로파일의 임계좌굴특성)

  • Jeong, Hyeon-Sik;No, In-Soo;Lee, Yeong-Seang
    • Journal of the Korean Geotechnical Society
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    • v.31 no.9
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    • pp.39-51
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    • 2015
  • various soil conditions as its application to foundation retrofit works has increased. However, most of the domestic researches focused mainly on bearing behavior of Case-I and Case-II type micropiles, whereas structural verification research was insufficient in relation with bulking behavior in particular. In this respect, this study was perfomed to understand the critical buckling characteristics of micropiles under axial load with various steel bars and grout conditions. As a result, it was found that a critical buckling shear strength of a micropile increases for smaller diameter micropile and a critical buckling load decreases with a longer length in the condition under the critical buckling length. Also, a method to evaluate a buckling possibility and yield behavior under axial compressive load conditions is proposed.

Inelastic Cyclic Behavior of Locally Buckled Steel Members (국부좌굴된 강구조부재의 비탄성 반복 거동)

  • Lee, Eun Taik;Song, Keum Jung
    • Journal of Korean Society of Steel Construction
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    • v.17 no.2 s.75
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    • pp.139-149
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    • 2005
  • Post-local buckling behavior is a very important consideration in plastic and seismic design of steel structures. It describes the structural behavior up to the final collapse state. In order to assess the actual reliability of structures under severe repeated loading, such as strong earthquakes, it is necessary to evaluate the progressive cyclic deterioration of stiffness as well as the strength and energy dissipation capacity of the structures after local buckling happens. In this study, a simple analytical model developed for predicting post-local buckling behavior for cyclic and non-proportional loading histories, has been proposed. This analytical model uses the stress resultant model based on the two surface model. Analytical moment-curvature relationship using this model compare well with the experimental results in constant amplitude cycling, and linearized energy deterioration which is very important in seismic design can be predicted from the proposed model.

Finite Element Analyses on Local Buckling Strength of Polygonal-Section Shell Towers (축방향 압축을 받는 다각형 단면 쉘 기둥구조의 국부좌굴강도에 관한 해석적 연구)

  • Park, Seong-Mi;Choi, Byung-Ho
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.13 no.4
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    • pp.1900-1907
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    • 2012
  • Since the subpanels of polygonal-section shell have the corners of an obtuse angle larger than 90 degree unlike general plate or box-section structures, this could have an influence on forming nodal lines against local plate buckling or stress distributions. However, there is not sufficient material in the relevant study results or design recommendations. The very feasible models of the initial imperfections were acquired through the literature studies and then the parametric studies were conducted along with the initial imperfection models by using the finite element method. The parameters like the size of residual stresses, the portion of compressive residual stresses, and steel grades were considered. From the parametric studies, it was found that the maximum residual stress is more influential factor than the distribution pattern of residual stresses. In addition, The design strength equations for the simply supported plates can be applicable to the determination of the local buckling strength of the polygonal cross-section shell structures.

Effect of Stiffener's Web Height against Axial Compression Ultimate Strength Considering Lateral Pressure Load (횡하중을 고려한 압축최종강도에 대한 보강재 치수의 영향)

  • Oh, Young-Cheol;Ko, Jae-Yong;Oh, Dong-Ki
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.14 no.1
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    • pp.89-93
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    • 2008
  • Stiffened panels are basic strength members which have been used widely in a vessel or an offshore. They have been used often a deck, a side and a bottom structure of ship and have a number of one sided stiffener in either one or both directions called grillage. Their buckling and plastic collapse become damaged reason of the hull girder so it needs to investigate accurately buckling and ultimate strength of stiffened panels. In the present paper, using the ANSYS, a commercial finite element analysis code, we conducted the evaluation regarding buckling and post-buckling behaviour of stiffened panels, and analyzed stiffener's web height change, considering the effect of lateral pressure load against compression ultimate strength.

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A study on the optimization of manufacturing processes of double wall bellows for dual fuel engine I - Design optimization by buckling and stress analysis - (Dual Fuel 엔진용 이중관 벨로우즈 제작 공정의 최적화에 관한 연구 I - 좌굴해석 및 응력해석을 통한 설계 최적화 -)

  • Kim, Pyung-Su;Kim, Jong-Do
    • Journal of Advanced Marine Engineering and Technology
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    • v.40 no.6
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    • pp.499-503
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    • 2016
  • Dual fuel engines are suitable for stricter regulations as they significantly decrease exhaust gas output. Hence, research and development of double wall bellows for dual fuel engines is important. In this study, optimum forming methods and welding conditions were derived to develop double wall bellows made of austenite stainless steel. The reliability of the prototypes was ensured by various performance evaluations. In this study, the buckling load and bellows stress were obtained by structural design, buckling, and stress analysis to design optimum bellows. As a result, the buckling load in the embossing shape of bellows increased by approximately 1.6 times, and no buckling and squirming occurred at 30.0 bar, which was twice that of the maximum design pressure.

A Study on Shear and Flexural Performance Evaluation of Circularly Corrugated Plate (원형 파형강판의 전단 및 휨 성능평가에 관한 연구 -전단 및 휨강도 설계식 제안-)

  • Moon, Seong Hwan;Oh, Sang Hoon
    • Journal of Korean Society of Steel Construction
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    • v.27 no.5
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    • pp.455-470
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    • 2015
  • This research suggest method to calculate more accurate shearing and bending force on corrugated steel plate that it is produced domestically. This research analyze limitation of former formula on domestic design standard and existing research. In addition The strength calculation formula on corrugated steel plate was proposed according to result of the experiment and FEM analysis. In this study, the result that compare experiment with analysis using the proposed shear buckling coefficient and limit width to thickness ratio indicate similar behavior. As the result of the research, It is judged that the structural member design and performance evaluation of the corrugated steel plate was conveniently applied.

Shear Strength of Plate Girder (플레이트거더의 전단내력)

  • Choi, Chui-Kyung;Kim, Kyu-Suk
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.7 no.2
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    • pp.169-176
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    • 2003
  • In the design of plate girder web panels, it is required to evaluate accurately the elastic buckling strength under shear, whether or not the post-buckling strength is accounted for. Currently, elastic shear buckling coefficient of web panels stiffened by transverse intermediate stiffeners are determined by assuming conservatively that web panels are simply supported at the juncture between the flange and web. Although the notion of the real boundary condition at the juncture of the web and the flanges to be somewhere between simple and fixed has been recognized from early days, the boundary condition has been conservatively assumed, mainly due to lack of means to evaluate it in a rational manner. In this paper, a series of numerical analyses and experiments is carried out to provide a simple equation with some parameters especially the flange-web thickness ratio.