• 제목/요약/키워드: Plastic Buckling

검색결과 333건 처리시간 0.023초

Seismic performance of 1/4-scale RC frames subjected to axial and cyclic reversed lateral loads

  • Bechtoula, Hakim;Sakashita, Masanobu;Kono, Susumu;Watanabe, Fumio
    • Computers and Concrete
    • /
    • 제2권2호
    • /
    • pp.147-164
    • /
    • 2005
  • This paper summarizes an experimental study on the seismic behavior of lower stories of a mid-rise reinforced concrete frame building. Two reinforced concrete frames with two stories and one span were tested and each frame represents lower two stories of an 11-story RC frame building. Both frames were designed in accordance with Japanese design guidelines and were identical except in the variation of axial force. The tests demonstrated that the overall load-displacement relations of the two frames were nearly the same and the first-story column shear was closely related to the column axial load. The columns and beams elongated during both of the tests, with the second-floor beam elongation exceeding 1.5% of the beam clear span length. The frame with higher axial loads developed more cracks that the frame under moderate axial load.

분기좌굴이론을 이용한 박판성형공정에서의 주름발생해석 (An analysis of the wrinkling initiation in sheet metal forming using bifurcation theory)

  • 김종봉;양동렬;윤정환
    • 한국소성가공학회:학술대회논문집
    • /
    • 한국소성가공학회 1998년도 춘계학술대회논문집
    • /
    • pp.28-31
    • /
    • 1998
  • Wrinkling is one of the major defects in sheet metal products and may be also attributable to the wear of the tool. The initiation and growth of the wrinkles are influenced by many factors such as stress state, mechanical properites of the sheet material, geometry of the body, and contact condition. It is difficult to analyze the wrinkling initiation and growth considering the factors because the effects of the factors are very complex and the wrinkling behavior may show wide variation for small deviation of the factors. In this study, the bifurcation theory is introduced for the finite element analysis of wrinkling initiation and growth, All the above mentioned factors are conveniently considered by finite element method. The finite element formulation is based on the incremental deformation theory and elastic-plastic material modeling. The finite element analysis is carried out using the continuum-based resultant shell elements considering the planar anisotropy of the sheet metal. The proposed method is verified by employing to column buckling problem. And then, the initiation and growth of wrinkling in deep drawing of cylindrical cup are analyzed.

  • PDF

Effect of stiffeners on failure analyses of optimally designed perforated steel beams

  • Erdal, Ferhat
    • Steel and Composite Structures
    • /
    • 제22권1호
    • /
    • pp.183-201
    • /
    • 2016
  • Perforated steel beams can be optimised by increased beam depth and the moment of inertia combined with a reduced web thickness, favouring the use of original I-section beams. The designers are often confronted with situations where optimisation cannot be carried out effectively, taking account of the buckling risk at web posts, moment-shear transfers and local plastic deformations on the transverse holes of the openings. The purpose of this study is to suggest solutions for reducing these failure risks of tested optimal designed beams under applying loads in a self-reacting frame. The design method for the beams is the hunting search optimisation technique, and the design constraints are implemented from BS 5950 provisions. Therefore, I have aimed to explore the strengthening effects of reinforced openings with ring stiffeners, welded vertical simple plates on the web posts and horizontal plates around the openings on the ultimate load carrying capacities of optimally designed perforated steel beams. Test results have shown that compared to lateral stiffeners, ring and vertical stiffeners significantly increase the loadcarrying capacity of perforated steel beams.

On the large plastic deformation of tubular beams under impact loading

  • Wang, B.
    • Structural Engineering and Mechanics
    • /
    • 제3권5호
    • /
    • pp.463-474
    • /
    • 1995
  • When a tubular cantilever beam is loaded by a dynamic force applied transversely at its tip, the strain hardening of the material tends to increase the load carrying capacity and local buckling and cross-sectional overlization occurring in the tube section tends to reduce the moment carrying capacity and results in structural softening. A theoretical model is presented in this paper to analyze the deformation of a tubular beam in a dynamic response mode. Based on a large deflection analysis, the hardening/softening M-${\kappa}$ relationship is introduced. The main interest is on the curvature development history and the deformed configuration of the beam.

Integrity of the Reactor Vessel Support System for a Postulated Reactor Vessel Closure Head Drop Event

  • Kim, Tae-Wan;Lee, Ki-Young;Lee, Dae-Hee;Kim, Kang-Soo
    • Nuclear Engineering and Technology
    • /
    • 제28권6호
    • /
    • pp.576-582
    • /
    • 1996
  • The integrity of reactor vessel support system of the Korean Standard Nuclear Power Plant (KSNPP) is investigated for a postulated reactor vessel closure head drop event. The closure head is disassembled from the reactor vessel during refueling process or general inspection of reactor vessel and internal structures, and carried to proposed location by the head lift rig. A postulated closure head drop event could be anticipated during closure head handling process. The drop event may cause an impact load on the reactor vessel and supporting system. The integrity of the supporting system is directly relevant to that of reactor vessel and reactor internals including fuels. Results derived by elastic impact analysis, linear and non-linear buckling analysis and elasto-plastic stress analysis of the supporting system implied that the integrity of the reactor vessel supporting system is intact for a postulated reactor vessel closure head drop event.

  • PDF

축압축력을 받는 원통형 축대칭 쉘구조의 거동에 관한 연구 (A Study on the Behavior of Cylindrical Shell Structure Subjected to Axial Compression)

  • 조현영;정진환;황상필
    • 한국전산구조공학회:학술대회논문집
    • /
    • 한국전산구조공학회 1997년도 가을 학술발표회 논문집
    • /
    • pp.249-253
    • /
    • 1997
  • A numerical method for evaluating the equilibrium path of cylindrical shell subject to axial load and eccentrically axial load is presented. The effects of both material and geometric nonlinearities were also considered in the analysis. The nonlinear formulation was based on the total Lagrangian description and nonlinear equtions were solved by the Newton-Raphson method with load increment procedures. Degenerate shell elements with layered approach were employed for the analysis. The elasto-plastic deformation can be found in several examples and a large eccentricity of the axial load reduces the stress level at the time of the local buckling of the pipe considerably.

  • PDF

정사각형 컵 디프드로잉의 탄소성 유한 요소해석 (An Elastic-Plastic FE Analysis of a Square Cup Deep Drawing Process)

  • 서의권;심현보
    • 소성∙가공
    • /
    • 제5권1호
    • /
    • pp.8-17
    • /
    • 1996
  • In the present study SEAM (Shear Energy Augmented Membrane) elements have been devel-oped. Maintaining the numerical efficiency of conventional membrane elements the effect of out-of-plane deformation (transverse shear deformation) has been incorporated for the purpose of computational stabilization without introducing additional degrees of freedom. Computations are carried out for the deep drawings of square cup to check the validity and the effectiveness of proposed SEAM elements. The computational results are compared with both the existing results. And the effects of process variables like initial sheet thickness punch & die round and clearance are checked

  • PDF

감육된 탄소강배관의 변형과 파괴거동 (Deformation and Fracture Behavior of Wall Thinned Carbon Steel Pipes)

  • 안석환;남기우
    • 한국해양공학회지
    • /
    • 제20권4호
    • /
    • pp.17-23
    • /
    • 2006
  • Monotonic four-point bending tests were conducted on straight pipe specimens, 102 mm in diameter with local wall thinning, in order to investigate the effects of the depth, shape, and location of wall thinning on the deformation and failure behavior of pipes. The local wall thinning simulated natural erosion/corrosion metal loss. The deformation and fracture behavior of the straight pipes with local wall thinning was compared with that of non wall-thinning pipes. The failure modes were classifiedas local buckling, ovalization, or crack initiation, depending on the depth, shape, and location of the local wall thinning. Three-dimensional elasto-plastic analyses were carried out using the finite element method. The deformation and failure behavior, simulated by finite element analyses, coincided with the experimental results.

Repaired concrete columns with fiber reinforced thixotropic mortar: experimental & FEA approach

  • Achillopoulou, Dimitra V.;Arvanitidou, Konstantinia C.;Karabinis, Athanasios I.
    • Computers and Concrete
    • /
    • 제15권1호
    • /
    • pp.73-88
    • /
    • 2015
  • Following previous studies, the current paper describes the results of an experimental program concerning the repair of reinforced concrete columns by thixotropic pseudo plastic mortar, preformed to analyze and quantify the influence of initial construction damage to the behavior of the repaired element. Five columns (section scale 1:2) were designed according to the minimum requirements of reinforcement of ductility orientated codes' design with variables the percentages of initial construction damages. All were tested in axial compression with repeated cycles up to failure. For comparison reasons, another one of the same characteristics, yet healthy, was constructed and tested as a reference specimen. A numerical study (Finite Element Analysis) was conducted for further investigation of the behavior of the thixotropic mortar as repair material. The results indicate that: a) surpassing a specific amount of damage, columns even suitably repaired present lower strain capacity, b) finite element analysis present the same way of deboning of the repaired material taking into consideration the buckling of the reinforcement bars.

라인파이프 강관의 압축-휨 좌굴 성능 평가 기법 개발 (Development of an Evaluation Method for the Compressive-Bending Plastic Buckling Capacity of Pipeline Steel Tube)

  • 지광습;이승정;윤영철;황상수;조우연
    • 한국전산구조공학회:학술대회논문집
    • /
    • 한국전산구조공학회 2010년도 정기 학술대회
    • /
    • pp.613-616
    • /
    • 2010
  • 본 논문에서는 라인파이프 강관의 압축-휨 좌굴 성능 평가 기법을 개발하기 위해 비선형 유한요소해석을 사용하였다. 고강도 강재의 연성거동을 모사하기 위해 범용 유한요소해석 프로그램인 ABAQUS의 사용자 재료모델을 사용하여 GTN(Gurson-Tvergaad-Needleman) 모델을 작성하였다. 실험결과와의 비교를 통해 재료모델상수를 결정하였으며 압축-휨 좌굴 실험의 모사에 사용하였다. 압축-휨 좌굴 성능 평가는 비선형 유한요소해석의 결과로부터 얻어진 한계압축변형률과 최대휨모멘트를 기준으로 수행될 수 있다. 개발된 성능 평가 기법은 고강도 강재를 이용한 라인파이프의 설계 시 대변형 거동 분석에 유용하게 사용될 수 있다.

  • PDF