• Title/Summary/Keyword: restraint

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Inelastic lateral-distortional buckling of continuously restrained continuous beams

  • Lee, Dong-Sik
    • Steel and Composite Structures
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    • v.5 no.4
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    • pp.305-326
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    • 2005
  • The inelastic buckling behaviour of continuously restrained two and three-span continuous beams subjected to concentrated loads and uniformly distributed loads are studied in this paper. The restraint type considered in this paper is fully restrained against translation and elastic twist applied at the top flange. These types of restraints are most likely experienced in industrial structures, for example steel-concrete composite beams and half through girders. The buckling analysis of continuous beam consists of two parts, firstly the moment and shear distribution along the member are determined by employing force method and the information is then used for an out-of-plane buckling analysis. The finite element method is incorporated with so-called simplified and the polynomial pattern of residual stress. Owing to the inelastic response of the steel, both the in-plane and out-of-plane analysis, which is treated as being uncoupled, extend into the nonlinear range. This paper presents the results of inelastic lateral-torsional and lateral-distortional buckling load and finally conclusions are drawn regarding the web distortion.

Shear buckling analysis of cross-ply laminated plates resting on Pasternak foundation

  • Topal, Umut;Nazarimofrad, Ebrahim;Kholerdi, Seyed Ebrahim Sadat
    • Structural Engineering and Mechanics
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    • v.68 no.3
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    • pp.369-375
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    • 2018
  • This paper presents the shear buckling analysis of symmetrically laminated cross-ply plates resting on Pasternak foundation under pure in-plane uniform shear load. The classical laminated plate theory is used for the shear buckling analysis of laminated plates. The Rayleigh-Ritz method with novel plate shape functions is proposed to solve the differential equations and a computer programming is developed to obtain the shear buckling loads. Finally, the effects of the plate aspect ratios, boundary conditions, rotational restraint stiffness, translational restraint stiffness, thickness ratios, modulus ratios and foundation parameters on the shear buckling of the laminated plates are investigated.

CWR for Seoul Subway No 2 DangSan Bridge by ZLR (Zero Longitudinal Restraint) (종방향 활동체결구를 사용한 당산철교 장대레일화 사례)

  • Lee Duck Young;Kong Sun Yong;Kwon Soon Sub;Kim Eun
    • Proceedings of the KSR Conference
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    • 2003.10b
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    • pp.379-384
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    • 2003
  • DangSan Bridge of Seoul Subway No 2 was rebuilt by safety reason. From Dec 1996 to Dec 1999 we were in charge of permanent way design of this rebuilt project. Especially we applied maintenance free system on the bridge by Cologne Egg alternative (ALT1) base plate and CWR (Continuous Welded Rail) by ZLR(Zero Longitudinal Restraint) for 125m (south approach section), 120m long(north approach section). This thesis generally introduce for CWR by ZLR which was first adapted CWR system in Korea.

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Effect of Chemical Restraint Drugs on Gastroduodenal Transit Time of Barium Sulfate in Cats (고양이에서 진정제 및 마취제가 Barium Sulfate의 위 십이지장 통과시간에 미치는 영향)

  • Yun Jeong-Hee;Sung Jai-Ki
    • Journal of Veterinary Clinics
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    • v.6 no.1
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    • pp.173-184
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    • 1989
  • The effect of propionylpromazine, acepromazine maleate, ketamine HCI, xylazine HCI, and pentobarbital sodium as chemical restraint drugs on the transit time of barium sulfate through the stomach and duodenum in 24 healthy cats was investigated. In the present study, propionylpromazine, acepromazine maleate, and ketamine HCI did not reveal significant effect on the gastroduodenal transit time, but xylazine HCI and pentobarbital sodium pro-longed the gastroduodenal transit time markedly compared with control group. Therefore it is concluded that propionylpromazine, acepromazine maleate, and ketamine HCI could be selected for upper gastrointestinal radiographs. but xylazine HCI and pentobarbital sodium should be avoided.

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Buckling behaviour of plates partially restrained against rotation under stress gradient

  • Bedair, Osama K.
    • Structural Engineering and Mechanics
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    • v.4 no.4
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    • pp.383-396
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    • 1996
  • In this paper, the behavior of plates partially restrained against rotation under stress gradient is investigated. As a first stage, an energy formulation is presented to model this boundary condition and a general expression is derived for the prediction of the elastic buckling of the plate under this general loading condition. The accuracy of the derived expression is compared numerically using the Galerkin method with other available data for the two limiting conditions of rotationally free and clamped boundaries. Results show that the prediction is within a 5% difference. The influence of rotational restraint and stress gradient upon the buckling load and the associated buckling mode is investigated. Numerical results show sensitivity of the buckling mode to the degree of rotational restraint and the variation of the buckling load with the stress gradient.

Study on the Measurement of Restraining and Opening Forces in Drawbeads (드로우비드 상압력과 인출력 측정에 관한 연구)

  • Moon, S.J.;Keum, Y.T.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2006.05a
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    • pp.203-206
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    • 2006
  • The drawbeads, which is used for controlling the flow of the sheet by imposing the tension and for preventing the springback in the sheet metal forming process, affects a lot the formability because of the differences in the restraint and opening forces according to the drawbead shapes and dimensions. In this study, the experimental device enabling to measure the drawbead restraining forces and the drawbead opening forces associated with various drawbead shapes and dimensions and their theoretical evaluation are introduced and verified through the experimental measurement of those of a circular drawbead.

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Effect of Admixtures on Drying Shrinkage Crack of Hardened Cement Mortar (시멘트경화체의 건조수축균열에 미치는 혼화재의 영향)

  • 이승한;이종석
    • Proceedings of the Korea Concrete Institute Conference
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    • 1995.10a
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    • pp.229-233
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    • 1995
  • In this study we have the properties of drying shrinkage crack of hardened cement mortar using admixtures. The drying shrinkage cracking test process has been examined by the restrained drying shrinkage strain by restraining rate measuring properties of strain-with- restraint by JIS original proposal and keeps a flow value of mortar about 100$\pm$5%. The results show that the usage of shrinkage reducing agent 1.5% was effective on the control of drying shrinkage in OPC and CP by restraining rate 20% and strain-with-restraing 20~30 $\mu$, the usage of expansion agent 0.45% was effective by restraining rate 50~60% and strain-with-restraint 40~80$\mu$, and the effectiveness was increased with shrinkage reducing agent. Also. admixtures such as Flyash, CP and NC reduced restrained shrinkage and drying shrinkage cracking and more with shrinkage reducing agent

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A Measurement of restraint force during the heating and cooling cycle of the welding process (박판 용접시 온도변화에 따른 구속력 측정)

  • 고준빈;이영호
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.10 no.1
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    • pp.94-100
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    • 2001
  • Distortion is a potential problem with all welded fabrication and should be caused dimensional changes and mismatch of joints during welding fabrication. Correction unacceptable weld distortion is extremely costly and in some case impossible. The aim of the present work is to verify the variation of the compressive force, tensile force and distortion during plastic deformation under Tungsten-inert-gas(TIG) welding, on type 304 stainless steel. Experimental results show that possibili-ty if measuring deformation during welding and good correlation was found between analytical and experimental result ad finite element methods have been used to model temperature analysis.

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Evidence-based Clinical Practice Protocol of Physical Restraints by Adaptation Process for Patients in a Geriatric Hospital (요양병원 입원 노인을 위한 신체 억제대 프로토콜의 수용개작)

  • Park, Mi Hwa;Sohng, Kyeong-Yae
    • The Korean Journal of Rehabilitation Nursing
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    • v.19 no.2
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    • pp.118-127
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    • 2016
  • Purpose: This study was to develop an evidence-based clinical practice protocol of physical restraints by adaptation process for patients with a geriatric hospital. Methods: Protocol adaptation process was conducted in accordance with manual for guideline adaptation version 1.0 by ADAPTE collaboration. Results: The adapted physical restraint protocol was consisted of 3 domains and 37 recommendations. The number of recommendations in each domain were: 7 nursing assessment, 19 nursing intervention, and 11 nursing evaluation. More than half (56.8%) of the recommendations were rated as grade B, 37.8% as grade C, and 5.4% were rated as grade D. Conclusion: The adapted physical restraint protocol is expected to contribute as an evidence-based clinical practice protocol for healthcare workers in geriatric hospitals for reducing and improving efficiency of appropriate physical restraints use.

Numerical Algorithm for Power Transformer Protection

  • Park, Chul-Won;Suh, Hee-Seok;Shin, Myong-Chul
    • KIEE International Transactions on Power Engineering
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    • v.4A no.3
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    • pp.146-151
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    • 2004
  • The most widely used primary protection for the internal fault detection of the power transformer is current ratio differential relaying (CRDR) with harmonic restraint. However, the second harmonic component could be decreased by magnetizing inrush when there have been changes to the material of the iron core or its design methodology. The higher the capacitance of the high voltage status and underground distribution, the more the differential current includes the second harmonic during the occurrence of an internal fault. Therefore, the conventional second harmonic restraint CRDR must be modified. This paper proposes a numerical algorithm for enhanced power transformer protection. This algorithm enables a clear distinction regarding internal faults as well as magnetizing inrush and steady state. It does this by analyzing the RMS fluctuation of terminal voltage, instantaneous value of the differential current, RMS changes, harmonic component analysis of differential current, and analysis of flux-differential slope characteristics. Based on the results of testing with WatATP99 simulation data, the proposed algorithm demonstrated more rapid and reliable performance.