• 제목/요약/키워드: Plastic collapse

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철근콘크리트 골조의 연성화 해석 (Softening Analysis of Reinforced Concrete Frames)

  • 나유성;홍성걸
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 1998년도 가을 학술발표논문집(II)
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    • pp.438-443
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    • 1998
  • Softening os the name used for decreasing bending moment at advanced flexural deformation. To accommodate softening deformation in analysis, it is assumed that a hinge has finite length. The softening analysis of R/C frames relies on the primary assumption that softening occurs over a finite hinge length and that the moment-curvature relationship for any section may be closely described by a trilinear approximation. A stiffness matrix for elastic element with softening regions are derived and the stiffness matrix allows extension of the capability of an existing computer program for elastic-plastic analysis to the softening situation. The effect of softening on the collapse load of R/C frame is evaluated.

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조합하중을 받는 해양구조물 원통부재의 최동강도 해석 (Utimate strength analysis of cylindrical members of offshore structure subject to combined loads)

  • 박치모
    • 한국해양공학회지
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    • 제11권2호
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    • pp.11-17
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    • 1997
  • Simple and efficient way of nonlinear analysis considering elasto-plastic large deformation is introduced to calculate the strength of ring-stiffened cylinears subject to combined load of axial compression and lateral pressure. Parametric study gives various collapse modes according to the combination ratio of axial compression and lateral pressure, interaction between axial compression and lateral pressure and imperfection sensitivity of ultimate strength.

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철근콘크리트 골조 비선형해석의 새로운 기법 (New Approach for Nonlinear Analysis of Reinforced Concrete Frames)

  • 김진근;이태규;양주경
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 1992년도 봄 학술발표회 논문집
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    • pp.47-52
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    • 1992
  • The entire nonlinear behavior of reinforced concrete frames up to collapse, is analyzed by the displacement control method and the combined layered and nonlayered method. All of the rigidities of section are calculated approximately by a sum over all the layers for the layered method, are used the integral values over the cross section area for the nonlayered method. The spurious sensitivity to the chosen element size in the result of analysis by finite element method for the materials with strain-softening can be overcome by modifying the strain distribution based on the concept of fracture energy at plastic hinge considering the applied axial load.

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The Energy Absorption of Combined Structure Subjected to Axial Compression

  • J.W.,Lee
    • 대한조선학회지
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    • 제19권4호
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    • pp.1-10
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    • 1982
  • An experimental investigation on the energy absorption of two staged combined structures is presented, which deals with the plastic collapse test as a series of research on soft bow structure involved in a ship collision. The principle of arithmetic superposition of energy absorption is derived upon experimental analysis and based upon the characteristics of the energy absorptions of component structures. This relationship is related to the further approach toward the design of soft bow.

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Late avulsion of a free flap in a patient with severe psychiatric illness: Establishing a successful salvage strategy

  • Schaffer, Clara;Hart, Andrew;Watfa, William;Raffoul, Wassim;Summa, Pietro Giovanni di
    • Archives of Plastic Surgery
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    • 제46권6호
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    • pp.589-593
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    • 2019
  • Post-traumatic defects of the distal third of the leg often require skipping a few steps of the well-established reconstructive ladder, due to the limited local reliable reconstructive options. In rare cases, the reconstructive plan and flap choice may encounter challenges when the patient has psychiatric illness affecting compliance with postoperative care. We describe a case of a patient with severe intellectual disability and an open fracture of the distal lower limb. After fracture management and debridement of devitalized tissues, the resultant soft tissue defect was covered with a free gracilis flap. On postoperative day 7, the patient ripped out the newly transplanted flap. The flap was too traumatized for salvage, so a contralateral free gracilis muscle flap was used. The patient showed good aesthetic and functional outcomes at a 1-year follow-up. When planning the postoperative management of patients with psychiatric illness, less complex and more robust procedures may be preferred over a long and complex surgical reconstruction requiring good compliance with postoperative care. The medical team should be aware of the risk of postoperative collapse, focus on the prevention of pain, and be wary of drug interactions. Whenever necessary, free tissue transfer should be performed despite potential compliance issues.

평면(平面) 뼈대 구조물(構造物) 소성해석(塑性解析) 및 최소중량(最小重量) 설계(設計) (Plastic Analysis and Minimum Weight Design of Plane Frame Structures)

  • 이동환;양창현;황원섭
    • 대한토목학회논문집
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    • 제6권2호
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    • pp.111-120
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    • 1986
  • 강재(鋼材) 뼈대 구조물(構造物)은 널리 사용(使用)되는 기본적(基本的)인 구조물(構造物)로서, 소성(塑性)힌지의 개념(槪念)을 도입(導入)한 설계(設計) 및 해석방법(解析方法)이 적절(適切)히 적용(適用)되고 있는 경우(境遇)라고 볼 수 있다. 소성해석(塑性解析)의 목적(目的)은 구조물(構造物) 각(各) 부재(部材)의 소성(塑性)모멘트를 알고 있을 때 붕괴하중(崩壞荷重)을 결정(決定)하는 것이며, 소성최적설계(塑性最適設計)의 목적(目的)은 구조물(構造物)의 총중량(總重量)을 최소(最小)로 하는 부도재(部都材)의 소성(塑性)모멘트를 결정(決定)하는 것이다. 본(本) 논문(論文)에서는 소성해석(塑性解析) 및 최적설계(最適設計)를 정적접근방법(靜的接近方法)(static approach)을 사용(使用)하여 Simplex method에 의해 해결(解決)하였다. 소성해석(塑性解析)의 경우(境遇), 종래(從來)의 계산시간(計算時間)을 훨씬 줄일 수 있었으며, 또한 본(本) 연구(硏究)에서 2층 구조물(構造物)의 최적설계시(最適設計時) 구조물(構造物)의 중량(重量)은 탄성설계(彈性設計)와 비교(比較)하여 약(約) 24%가 절약(節約)되었다.

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적층구성 변화에 따른 경량화 구조부재의 에너지 흡수 특성 (A Study on Energy Absorption Characteristics of Lightweight Structural Member according to Stacking Conditions)

  • 최주호;양인영
    • 한국생산제조학회지
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    • 제21권2호
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    • pp.241-245
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    • 2012
  • In this study, one type of circular shaped composite tube was used, combined with reinforcing foam and without foam. Furthermore, CFRP (Carbon Fiber Reinforced Plastic) circular member manufactured from CFRP prepreg sheet for lightweight design. CFRP is an anisotropic material which is the most widely adapted lightweight structural member. The crashworthy behavior of circular composite material tubes subjected to static axial compression under same conditions is reported in this paper. The collapse mode during the failure process were observed and analyzed. The behavior of polymeric foams to the tubes crashworthiness were also investigated.

Stress resultant model for ultimate load design of reinforced-concrete frames: combined axial force and bending moment

  • Pham, Ba-Hung;Davenne, Luc;Brancherie, Delphine;Ibrahimbegovic, Adnan
    • Computers and Concrete
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    • 제7권4호
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    • pp.303-315
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    • 2010
  • In this paper, we present a new finite Timoshenko beam element with a model for ultimate load computation of reinforced concrete frames. The proposed model combines the descriptions of the diffuse plastic failure in the beam-column followed by the creation of plastic hinges due to the failure or collapse of the concrete and or the re-bars. A modified multi-scale analysis is performed in order to identify the parameters for stress-resultant-based macro model, which is used to described the behavior of the Timoshenko beam element. The micro-scale is described by using the multi-fiber elements with embedded strain discontinuities in mode 1, which would typically be triggered by bending failure mode. A special attention is paid to the influence of the axial force on the bending moment - rotation response, especially for the columns behavior computation.

Limit analysis of plates-a finite element formulation

  • Capsoni, Antonio;Corradi, Leone
    • Structural Engineering and Mechanics
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    • 제8권4호
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    • pp.325-341
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    • 1999
  • A procedure for the computation of the load carrying capacity of perfectly plastic plates in bending is presented. The approach, based on the kinematic theorem of limit analysis, requires the evaluation of the minimum of a convex, but non-smooth, function under linear equality constraints. A systematic solution procedure is devised, which detects and eliminates the finite elements which are predicted as rigid in the collapse mechanism, thus reducing the problem to the search for the minimum of a smooth and essentially unconstrained function of nodal velocities. Both Kirchhoff and Mindlin plate models are considered. The effectiveness of the approach is illustrated by means of some examples.