• Title/Summary/Keyword: Stiffness of frame

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Development of a Wall Analysis Model Grafting FE-BEM (FE-BEM을 결합한 벽체의 해석모델 개발)

  • Jung , Nam-Su;Choi, Won;Lee, Ho-Jae;Kim , Han-Joong;Lee , Jeong-Jae;Kim, Jong-Ok
    • Journal of The Korean Society of Agricultural Engineers
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    • v.46 no.5
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    • pp.61-68
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    • 2004
  • Methodologies of the finite element and boundary element are combined to achieve an efficient and accurate analysis model of frame structure containing shear wall. This model analyzes the frame by employing the finite element method and the shear wall by boundary element method. This study is applicable to a specific situation, where the boundary element is surrounded by finite elements. By employing FE dominant method in which boundary stiffness matrix is transformed into finite element stiffness matrix, boundary element and finite element method are combined to analyze frame structure with walls.

Seismic Analysis of Mid Rise Steel Moment Resisting Frames with Relative Stiffness of Connections and Beams (접합부와 보의 상대강성을 고려한 중층 철골 모멘트 골조의 내진해석)

  • Ha, Sung-Hwan;Kang, Cheol-Kyu;Han, Hong-Soo;Han, Kweon-Gyu;Choi, Byong-Jeong
    • Journal of Korean Society of Steel Construction
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    • v.23 no.5
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    • pp.595-606
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    • 2011
  • This study was conducted to investigate the seismic behavior of steel member resisting frames considering the relative stiffness of the connection and beams. Six-story steel moment frames were designed to study the seismic behavior. The connections were classified into Double Web-Angle connections (DWAs), Top- and Seat-angles with double Web-angles (TWSs), FEMA-Test Summary No. 28, Specimen ID: UCSD-6 (SAC), and Fully Restrained (FR). The rotational stiffness of the semi-rigid connections was estimated using the Three-Parameter Power Model adopted by Chen and Kishi. The relative stiffness, which is the ratio of the rotational stiffness of the connections to the stiffness of the beams, was used. Push-over, repeated loading, and time history analysis were performed for all the frames. The seismic behavior of each frame was analyzed with the story drift, plastic hinge rotation, and hysteretic energy distribution.

The Effect of Cross Beam on the strength and Stiffness of the Frame in Shuttle Car for LMIT (LMTT용 Suhttle Car의 Frame 강도 및 강성에 미치는 Cross Beam의 영향)

  • Lim J. H.;Han G. J.;Lee K. S.;Han D. S.;Shim J. J.;Lee S. W.;Jeon Y. H.
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2004.11a
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    • pp.323-328
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    • 2004
  • According as the quantity of goods transported by ship is increasing about $7\%$ per year, a port environment is rapidly changing. To meet this situation successfully, the development of the next generation port loading and unloading system (LMTT) is studied. A Frame of shuttle car for LMTT(Linear Motor-based Transfer Technology) consist of three parts which are outer beam inner beam and cross boom. Outer boom supports a container and inner boom is a framework and cross boom reinforces outer and inner boom. In this study, we carried out the finite element analysis for the effect of cross boom on the strength and stiffness qf the frame according to the number if cross beam leading position of container, the distance ratio if inner boom from center.

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Analysis of R/C frames considering cracking effect and plastic hinge formation

  • Kara, Ilker Fatih;Ashour, Ashraf F.;Dundar, Cengiz
    • Structural Engineering and Mechanics
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    • v.63 no.5
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    • pp.669-681
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    • 2017
  • The design of reinforced concrete buildings must satisfy the serviceability stiffness criteria in terms of maximum lateral deflections and inter story drift in order to prevent both structural and non-structural damages. Consideration of plastic hinge formation is also important to obtain accurate failure mechanism and ultimate strength of reinforced concrete frames. In the present study, an iterative procedure has been developed for the analysis of reinforced concrete frames with cracked elements and consideration of plastic hinge formation. The ACI and probability-based effective stiffness models are used for the effective moment of inertia of cracked members. Shear deformation effect is also considered, and the variation of shear stiffness due to cracking is evaluated by reduced shear stiffness models available in the literature. The analytical procedure has been demonstrated through the application to three reinforced concrete frame examples available in the literature. It has been shown that the iterative analytical procedure can provide accurate and efficient predictions of deflections and ultimate strength of the frames studied under lateral and vertical loads. The proposed procedure is also efficient from the viewpoint of computational time and convergence rate. The developed technique was able to accurately predict the locations and sequential development of plastic hinges in frames. The results also show that shear deformation can contribute significantly to frame deflections.

Effect of connection stiffness on the earthquake-induced progressive collapse

  • Ali, Seyedkazemi;Mohammad Motamedi, Hour
    • Earthquakes and Structures
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    • v.23 no.6
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    • pp.503-515
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    • 2022
  • Global or partial damage to a structure due to the failure of gravity or lateral load-bearing elements is called progressive collapse. In the present study, the alternate load path (ALP) method introduced by GSA and UFC 4-023-03 guidelines is used to evaluate the progressive collapse in special steel moment-resisting frame (SMRF) buildings. It was assumed that the progressive collapse is due to the earthquake force and its effects after the removal of the elements still remain on the structures. Therefore, nonlinear dynamic time history analysis employing 7 earthquake records is used to investigate this phenomenon. Internal and external column removal scenarios are investigated and the stiffness of the connections is changed from semi-rigid to rigid. The results of the analysis performed in the OpenSees program show that the loss of the bearing capacity of an exterior column due to a seismic event and the occurrence of progressive collapse can increase the inter-story drift of the structure with semi-rigid connections by more than 50% and make the structure unable to satisfy the life safety performance level. Furthermore, connection stiffness severely affects the redistribution of forces and moments in the adjacent elements of the removed column.

Structural Analysis and Optimization of a Low Speed Vehicle Body (저속차량 차체의 구조해석 및 구조최적설계)

  • 신정규;심진욱;황상진;박경진
    • Transactions of the Korean Society of Automotive Engineers
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    • v.11 no.4
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    • pp.68-78
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    • 2003
  • Recently, low speed vehicle (LSV) is beginning to appear for various usages. The body of the LSV is usually made of the aluminum space frame (ASF) type rather than the monocoque or unitary construction type. A pa.1 of the reason is that it is easier to reduce mass efficiently while the required stiffness and strength are maintained. A design flow for LSV is proposed. Design specifications for structural performances of LSV do not exist yet. Therefore, they are defined through a comparative study with general passenger automobiles. An optimization problem is formulated by the defined specifications. At first, one pillar which has an important role in structural performances is selected and the reinforcements of the pillar are determined from topology optimization to maximize the stiffness. At second, the thicknesses of cross sections are determined to minimize the mass of the body while design specifications are satisfied. The optimum solution is compared with an existing design. The optimization process has been performed using a commercial optimization software system, GENESIS 7.0.

An Analysis of Cylindrical Tank of Elastic Foundation by Transfer Matrix and Stiffness Matrix (전달행렬과 강성행렬에 의한 탄성지반상의 원형탱크해석)

  • 남문희;하대환;이관희;장홍득
    • Computational Structural Engineering
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    • v.10 no.1
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    • pp.193-200
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    • 1997
  • Even though there are many analysis methods of circular tanks on elastic foundation, the finite element method is widely used for that purpose. But the finite element method requires a number of memory spaces, computation time to solve large stiffness equations. In this study many the simplified methods(Analogy of Beam on Elastic Foundation, Foundation Stiffness Matrix, Finite Element Method and Transfer Matrix Method) are applied to analyze a circular tank on elastic foundation. By the given analysis methods, BEF analogy and foundation matrix method, the circular tank was transformed into the skeletonized frame structure. The frame structure was divided into several finite elements. The stiffness matrix of a finite element is related with the transfer matrix of the element. Thus, the transfer matrix of each finite element utilized the transfer matrix method to simplify the analysis of the tank. There were no significant difference in the results of two methods, the finite element method and the transfer matrix method. The transfer method applied to a circular tank on elastic foundation resulted in four simultaneous equations to solve completely.

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A Structural Analysis of C-Frame Press (C-Frame Press의 구조해석)

  • 박현기;황병복
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 1997.03a
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    • pp.257-260
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    • 1997
  • The high precision of the products manufatured by press forming requires the high stiffness of press machines. In this study, the C-frame type press is analyzed to provide the basic idea on the C-frame press design, especially on the frame design. The finite element method is applied for the analysis and the isotropic propertics of the frame material is also considered. The results are summarized in terms of stresses and displacement distributions. Also, the openback angle of the presses is compared with two different models. The CS-150 and ECS-150 models, which are presses model having 150 ton frame capacity relatively and produced by SSangYong precision Co. LTD, are applied for the analysis.

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Performance Evaluation of Steel Frame and Steel Damper Reinforced in RC frame (RC 골조에 보강된 강재프레임과 강재댐퍼의 성능 평가)

  • Lee, Hyun-Ho
    • Journal of Korean Association for Spatial Structures
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    • v.23 no.1
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    • pp.77-84
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    • 2023
  • In this study, the performance evaluation of the RC frame specimen (RV2) which was strengthened by a steel frame and a steel damper with the lateral deformation prevention details proceeded. The comparison objects are bare frame specimen (BF), RV2 and AWD, where AWD is a specimen reinforced with steel damper and aramid fiber sheets. In the evaluation of envelope curve, stiffness degradation, and energy dissipation capacity, RV2 was evaluated to have excellent capacity as a whole. To evaluate the strengthening effect of the steel frame based on the maximum strength and energy dissipation capacity, it was evaluated to have a 38% of the RV2's capacity.