• 제목/요약/키워드: load behavior

검색결과 5,397건 처리시간 0.029초

Stability behavior of the transmission line system under incremental dynamic wind load

  • Sarmasti, Hadi;Abedi, Karim;Chenaghlou, Mohammad Reza
    • Wind and Structures
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    • 제31권6호
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    • pp.509-522
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    • 2020
  • Wind load is the principal cause for a large number of the collapse of transmission lines around the world. The transmission line is traditionally designed for wind load according to a linear equivalent method, in which dynamic effects of wind are not appropriately included. Therefore, in the present study, incremental dynamic analysis is utilized to investigate the stability behavior of a 400 kV transmission line under wind load. In that case, the effects of vibration of cables and aerodynamic damping of cables were considered on the stability behavior of the transmission line. Superposition of the harmonic waves method was used to calculate the wind load. The corresponding wind speed to the beginning of the transmission line collapse was determined by incremental dynamic analysis. Also, the effect of the yawed wind was studied to determine the critical attack angle by the incremental dynamic method. The results show the collapse mechanisms of the transmission line and the maximum supportable wind speed, which is predicted 6m/s less than the design wind speed of the studied transmission line. Based on the numerical modeling results, a retrofitting method has been proposed to prevent failure of the tower members under design wind speed.

철근콘크리트 인장부재의 인장강성 및 파괴거동에 관한 연구 (Failure Behavior and Tension Stiffening of RC Tension Members)

  • 박제선;이봉학;윤경구;홍창우;이주형
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 1998년도 봄 학술발표회논문집(II)
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    • pp.737-742
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    • 1998
  • The tension stiffening effect is defined as the increase in stiffness in reinforced concrete member due to the stiffness provided by concrete between cracks. If this is disregarded in analysis of reinforced concrete members, especially at the level of service loads, member stiffnesses may be underestimated considerably. This paper presents on the failure behavior and tension stiffening of RC tension test with main variables such as concrete strength, rebar diameter and strength. The tension stiffening was analyzed from the load-displacement relationship by ACI code and the proposed by Collins & Mitchell. In summary, the effect of tension stiffening decrease rapidly as the rebar diameter increase, rebar strength increase, and concrete strength increase. The effect of tension stiffening on RC member is the biggest near the behavior of concrete cracking and decrease as the load close to the breaking point. Thus, the tension stiffening should be considered for the precise analysis near the load of concrete cracking.

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혼합모드 단일과대하중 하에서 피로균열 전파거동의 예측 (Prediction of Fatigue Crack Propagation Behavior Under Mixed-Mode Single Overload)

  • 이정무;송삼홍
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2004년도 추계학술대회
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    • pp.359-364
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    • 2004
  • In this study, experiments were tried on the mixed-mode I+II single overloading model which changes the loading mode of overload and fatigue load. Aspects of deformation field in front of the crack which is formed by mixed-mode I+II single overloading were experimentally studied. Then the shape and size of mixed-mode plastic zone were approximately calculated. The propagation behavior of fatigue crack was examined under the test conditions combined by changing the loading mode. The behavior of fatigue cracks were greatly affected by shapes of plastic deformation field and applying mode of fatigue load. Accuracy of prediction and evaluation for fatigue life may be improved by considering all aspects of deformation and behavior of fatigue cracks.

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구름접촉에 의한 SM55C의 마멸 거동 (Wear behavior of SM55C steel by rolling contact)

  • 박범수;채영훈;김석삼
    • 한국윤활학회:학술대회논문집
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    • 한국윤활학회 2002년도 제35회 춘계학술대회
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    • pp.240-247
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    • 2002
  • The rolling wear behavior of SM55C is investigated under lubrication. This is a comparative tribological behavior of heat treatment effect for SM55C. Rolling wear test method is used for Ball-on-disk type. Specimens can be classified into two main groups: as-annealing and non-annealing. As result of wear behavior, flanking initial time of non-annealing specimen keep at retard but it have not under high normal load. One of the notable features of annealing specimen is steady flanking initial time for a normal load in this experiment. Failure mechanism of SM55C is due to the fatigue wear such like flanking, pitting etc.. Flanking leads to abruptly fracture of worn surface. Fracture mechanism has a connection with normal load and polishing direction of specimens.

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굽힘하중을 받는 알루미늄 사각관 보의 국부적 좌굴붕괴 거동에 관한 연구 (A Study on the Local Buckling Collapse Behavior of an Aluminum Square Tube Beam under a Bending Load)

  • 이성혁;최낙삼
    • 대한기계학회논문집A
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    • 제27권12호
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    • pp.2011-2018
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    • 2003
  • To analyze the bending collapse behavior of an aluminum square tube beam under a bending load, a finite element simulation for the four-point bending test has been performed. Using an aluminum tube beam specimen partly inserted with two steel bars, the local buckling deformation near the center of the tube beam was induced. The maximum bending load and the bending collapse behavior obtained from the numerical simulation were in good agreement with experimental results. Using a combination of the four-point bending test and its finite element simulation, analysis of the local buckling and the accompanied bending collapse behavior of aluminum tube beam could be quantitative accomplished.

사각 관 구조물의 충격에 의한 좌굴특성 (Buckling Behavior of a Square Tube Structure by Lateral Impact Load)

  • 윤경호;송기남;강흥석
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2001년도 춘계학술대회논문집A
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    • pp.812-818
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    • 2001
  • The drop type impact test and finite element analysis are established for examining the buckling behavior of a square tube under the lateral impact load. Based on these results, the effects by the boundary conditions for supporting the structure are reviewed, which are as follows. One is pinned condition by screw; the other is fixed by welding. The critical impact force and acceleration by test are nearly same between two cases. However, the critical impact velocity of the pinned condition is higher than that of the fixed case. Therefore, the dynamic buckling behavior of a pinned structure is better than the fixed condition in view of critical impact velocity. These test and analysis results will be adaptable for predicting the dynamic structural integrity of a tube structure not only the axial impact event but the lateral impact event.

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주기하중을 받는 비보강 조적벽체의 강체회전거동 (Rocking Behavior of Unreinforced Masonry Walls Under Cyclic Load)

  • 엄태성;김진우;김선웅;김재환;한주연;최호
    • 한국지진공학회논문집
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    • 제27권1호
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    • pp.49-57
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    • 2023
  • This study investigated the rocking behavior of unreinforced masonry walls and wall piers under cyclic loading. Based on the benchmark tests, the characteristics of load-deformation relations in masonry walls with rocking failure were captured, focusing on observed deformation modes. The rocking strengths of masonry walls (i.e., peak and residual strengths) were evaluated, and the effects of opening configurations on the masonry wall strength were examined. The deformation capacity of the rocking behavior and the hysteresis shape of the load-deformation relations were also identified. Based on the results, modeling approaches for the rocking behavior of masonry walls were discussed.

증분형(增分形) 유한요소법(有限要素法)에 의한 축대칭(軸對稱) Shell구조(構造)의 좌굴해석(挫屈解析) (Buckling Analysis of Axisymmetric Shells by Incremental Finite Element Mothod)

  • 김재복;김창렬
    • 대한조선학회지
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    • 제22권1호
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    • pp.21-30
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    • 1985
  • This paper deals whth the buckling as well as postbuckling analysis of axisymmertric shells taking the initial deflection effects into account. Incremental equilibrium equations, based on the principle of virtual work, were derived by the finite element method, the successive step-by-step Newton-Raphson iterative technique was adopted. To define the transition pattern of postbuckling behavior from the prebuckling state more accurately, a simple solution method was developed, i.e. the critical load was calculated by the load extrapolation method with the determinant of tangent stiffness matrix and the equilibrium configuration in the immediate postbuckling stage was obtained by perturbation scheme and eigenvalue analysis. Degenerated isoparametric shell elements were used to analyse the axisymmetric shell of revolution. And by the method developed in this paper, the computer program applicable to the nonlinear analysis of both thin and moderately thick shells was constructed. To verify the capabilities and accuracies of the present solution method, the computed results were compared with the results of analytical solutions. These results coincided fairly well in both the small deflection and large deflection ranges. Various numerical analyses were done to show the effect of initial deflection and shape of shells on buckling load and postbuckling behavior. Futhermore, corrected directions of applied loads at every increment steps were used to determine the actual effects of large deflection in non-conservative load systems such as hydrostatic pressure load. The following conclusions can be obtained. (1) The method described in this paper was found to be both economic and effective in calculating buckling load and postbuckling behavior of shell structure. (2) Buckling and postbuckling behavior of spherical caps is critically dependent upon their geometric configuration, i.e. the shape of spherical cap and quantities of the initial deflection. (3) In the analysis of large deflection problems of shells by the incremental method, corrections of the applied load directions are needed at every incremental step to compensate the follower force effects.

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Behavior and modeling of single bolt lap-plate connections

  • Rex, Clinton O.;Easterling, W. Samuel
    • Steel and Composite Structures
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    • 제2권4호
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    • pp.277-296
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    • 2002
  • A research investigation of single bolt lap-plate connection load-deformation behavior is presented. Each important characteristic of this behavior is evaluated and two methods for analytically approximating the behavior are developed and presented. The first of these methods is a component method in which the behavior of the connection is modeled as a combination of the behavior of the parts. The second method utilizes a number of parametric relationships that relate the connection parameters to coefficients of two non-linear continuous analytical curves. The test results from four independent experimental programs that investigated the behavior of single bolt lap-plate connections are used in the development and verification of these methods.

Beam-column behavior of concrete filled steel tubes

  • Campione, G.;Scibilia, N.
    • Steel and Composite Structures
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    • 제2권4호
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    • pp.259-276
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    • 2002
  • In the present investigation the experimental and theoretical flexural and compressive behavior of short tubular steel columns filled with plain concrete and fiber-reinforced concrete (FRC) was examined. For a given length of the members, the effects of different geometry and dimensions of the transverse cross-section (square and circular) were investigated. Constituent materials were characterized through direct tensile tests on steel coupons and through compressive and split tension tests on concrete cylinders. Load-axial shortening and load-deflection curves were recorded for unfilled and composite members. Finally, simplified expressions for the calculus of the load-deflection curves based on the cross-section analysis were given and the ultimate load of short columns was predicted.