• Title/Summary/Keyword: Critical members

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The Elastic Critical Loads of Sinusolidally Tapered Symmetric Compression Members (정현상 대칭으로 Taper진 변단면 압축재의 임계하중)

  • 오금열;홍종국;김순철;이수곤
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2000.04b
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    • pp.27-34
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    • 2000
  • The elastic critical loads of prismatic compression members can be easily determined by the conventional analytic method. In the cases of sinusoidally tapered members, however, the determination of elastic critical loads become impossible when one relies on the analytic method. In this paper, the critical loads of sinusoidally tapered members were determined by finite element method. Generally the output or results of numerical analysis are valid only when the governing parameters of a given system(or problem) have particular values. To make the practical applications easy, the critical loads determined by finite element method are expressed by some algebraic equations. The constants contained in the algebraic equations were determined by regression technique. The elastic critical loads estimated by the proposed algebraic equations coincide well with those by finite element method.

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A Study on the Architectural Evaluation for the Commercial-Residential Complex - Focused on the Seoul Building Design Review - (주상복합건축물의 심의평가에 관한 연구 -서울시 건축(1)심의를 중심으로 -)

  • Cho Ja-Yeon
    • Journal of the Korean housing association
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    • v.17 no.2
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    • pp.143-150
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    • 2006
  • In this Study, it was investigated what the critical elements of the Architectural Review by the Seoul Building Design Committee were. The critical elements selected by the members of committee were systematically analyzed. They were based on the 169 cases reviewed by the Building Design Committee. The committee consists of Professors, famous architects, architectural experts and official members. Thus, the critical elements selected by the committee can be regarded as the important criteria for the forthcoming architectural reviewing process. The critical elements selected by 960 members of the committee were classified by the frequency. The results in this study showed that the critical elements were ordered as follows: (1)floor plan, (2)landscape gardening, (3)form, (4)open space, (5)structure, (6)plan for preventing disasters, (7)circulation for men and cars, (8)facilities, (9)parking, (10)revision of drawings and documents. These criteria of the architectural evaluation established by the Seoul Building Design Committee can be applied to the fundamental preparation of the architectural review.

The Elastic Critical Loads of Linearly Non-symmetrically Tapered Members (직선형으로 Taper진 비대칭 변단면 부재의 탄성임계하중)

  • 김효중;홍종국;이수곤
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2000.10a
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    • pp.299-306
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    • 2000
  • The elastic critical load of a slender compression member plays an important role when the proper design of that member is required. For tapered compression members, however, there are cases when the conventional neutral equilibrium or energy method can't be applied to the determination of critical loads. In this paper, the finite element method is applied to the approximate determination of the linearly tapered members. In this paper, the bars are assumed to be tapered linearly along their axes. The parameters considered in this study are taper parameter, α and the sectional property parameter, m. The member ends are either hinged or fixed. The computed results using the finite element method are represented in the forms of algebraic equations. The regression technique is employed to determine the coefficients of the algebraic equations. Critical loads estimated by the proposed algebraic equations coincide flirty well with those employing the finite element method.

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Critical Care Nurses' Perception of Life-sustaining Treatment at End of Life: A Content Analysis (생애 말 연명의료에 대한 중환자실 간호사의 인식: 내용 분석 연구)

  • Koh, Chin-Kang;Ko, Chung Mee;Park, Hyeyoung
    • Journal of Korean Critical Care Nursing
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    • v.10 no.1
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    • pp.41-50
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    • 2017
  • Purpose: The purpose of this study was to describe what critical care nurses perceived about life-sustaining treatment at end of life. Methods: A qualitative content analysis method was utilized. The unit of analysis was interview text obtained from fifty critical care nurses of a general hospital. Results: Seven categories in two content areas were abstracted. In the negative perception area, the following five categories were abstracted: patients' suffering, dying with damaged dignity, patients' isolation from family members, regret about choosing life-sustaining treatment, and family members' burden. In the positive perception area, the following two categories were abstracted: willingness to sustain life and duty as family members. Conclusions: Nurses have better competencies pertaining to understanding patients' responses and suffering than any other health care professions do. Nurses should play an important role in advocating for patients and their family in the process of end-of-life care decision making.

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Reliability of microwave towers against extreme winds

  • Deoliya, Rajesh;Datta, T.K.
    • Structural Engineering and Mechanics
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    • v.6 no.5
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    • pp.555-569
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    • 1998
  • The reliability of antenna tower designed for a n-year design wind speed is determined by considering the variability of the strength of the component members and of the mean wind speed. For obtaining the n-year design wind speed, maximum annual wind speed is assumed to follow Gumbel Type-1 distribution. Following this distribution of the wind speed, the mean and standard deviation of stresses in each component member are worked out. The variability of the strength of members is defined by means of the nominal strength and a coefficient of variation. The probability of failure of the critical members of tower is determined by the first order second moment method (FOSM) of reliability analysis. Using the above method, the reliability against allowable stress failure of the critical members as well as the system reliabilities for a 75 m tall antenna tower, designed for n-year design wind speed, are presented.

The ECBL approach for interactive buckling of thin-walled steel members

  • Dubina, Dan
    • Steel and Composite Structures
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    • v.1 no.1
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    • pp.75-96
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    • 2001
  • Actual buckling curves are always characterised by the erosion of ideal buckling curves. In case of compact sections this erosion is due to the imperfections, while for thin-walled members, a supplementary erosion is induced by the phenomenon of coupled instabilities. The ECBL approach- Erosion of Critical Bifurcation Load - represents a practical and convenient tool to characterise the instability behaviour of thin-walled members. The present state-of-art paper describes the theoretical background of this method and the applications to cold-formed steel sections in compression and bending. Special attention is paid to the evaluation methods of erosion coefficient and to their validation. The ECBL approach can be also used to the plastic-elastic interactive buckling of thin-walled members, and the paper provides significant results on this line.

Rayleigh-Ritz procedure for determination of the critical load of tapered columns

  • Marques, Liliana;Da Silva, Luis Simoes;Rebelo, Carlos
    • Steel and Composite Structures
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    • v.16 no.1
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    • pp.45-58
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    • 2014
  • EC3 provides several methodologies for the stability verification of members and frames. However, when dealing with the verification of non-uniform members in general, with tapered cross-section, irregular distribution of restraints, non-linear axis, castellated, etc., several difficulties are noted. Because there are yet no guidelines to overcome any of these issues, safety verification is conservative. In recent research from the authors of this paper, an Ayrton-Perry based procedure was proposed for the flexural buckling verification of web-tapered columns. However, in order to apply this procedure, Linear Buckling Analysis (LBA) of the tapered column must be performed for determination of the critical load. Because tapered members should lead to efficient structural solutions, it is therefore of major importance to provide simple and accurate formula for determination of the critical axial force of tapered columns. In this paper, firstly, the fourth order differential equation for non-uniform columns is derived. For the particular case of simply supported web-tapered columns subject to in-plane buckling, the Rayleigh-Ritz method is applied. Finally, and followed by a numerical parametric study, a formula for determination of the critical axial force of simply supported linearly web-tapered columns buckling in plane is proposed leading to differences up to 8% relatively to the LBA model.

CRITICAL PATHWAY ON GENERAL ANESTHESIA FOR DISABLED CHILDREN (장애아동 전신마취에 대한 Critical Pathway적용)

  • Kum, Jin-Eun;Lee, Su-Jin;Huh, Jeong-Ae;Jeong, Tae-Sung
    • The Journal of Korea Assosiation for Disability and Oral Health
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    • v.3 no.2
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    • pp.80-86
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    • 2007
  • A critical pathway (CP) defines the optimal care process, sequencing and timing of intervention by multi-disciplinary health care teams for a particular diagnosis and procedure. It plays an important role as a cost-effective health care delivery system and a tool for quality control of medical and dental services by means of standardizing medical practices. The aim of this study is to investigate the satisfaction of patients and medical/dental staff after implementation of a critical pathway for dental treatment of disabled children under general anesthesia and its cost effectiveness. Ten patients who underwent dental treatment under general anesthesia were included in the CP group between August and December 2006. The pre-CP group included 20 patients who underwent the same procedure from February 2003. The satisfaction of parent of child patient and medical staff members were compared between two groups. The parents' satisfaction was significantly improved after the implementation of CP and medical/dental staff members were highly satisfied with the usefulness of the critical pathway. In conclusion, the critical pathway for the dental treatment of disabled treatment under general anesthesia can highly improve the satisfaction of parents and medical/ dental staff members.

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Elastic Critical Load of Non-symmetrically Tapered Columns by Numerical Method (수치해석법에 의한 비대칭 변단면 기둥의 탄성 임계하중)

  • 신세욱;김선혜;이수곤
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 1999.04a
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    • pp.11-18
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    • 1999
  • For the proper design of a slender compression member, the exact determination of the elastic critical load is crucial, In the cases of non-prismatic compression members, the determinations of the elastic critical load cannot be usually expressed in closed forms. h this paper, the non-symmetrically tapered compression members with arbitrary boundary conditions me analysed by using the finite element method to determine the elastic critical load. The main parameters considered in the numerical analysis are the In Parameter, $\alpha$ and the sectional property parameter, m. To generaliza the unmerical analysis, of the computed results for each sectional parameter, m are presented in algebraic equations, which agrees fairy well with those by F.E.M in most cases.

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Elastic Critical Load of Tapered Columns (변단면 압축재의 임계하중)

  • 김태순;홍종국;김순철;이수곤
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 1999.10a
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    • pp.421-428
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    • 1999
  • The elastic critical load of a slender compression member plays an important role when the proper design of that member is required. For the tapered compression members, however, there are cases when the conventional neutral equililbrium or energy method can't be applied to the determination of critical loads of those members. In this paper, finite element method is applied to the approximate determination of the symmetrically tapered bars. Here in this paper, the bars are assumed to take sinusoidally changing shapes along their axes. The parameters considered in this study are taper parameter, $\alpha$ and the sectional property parameter, m. The computed results by finite element method are represented in the forms of algebraic equations. Regression technique is employed to determine the coefficients of algebraic equations. The critical loads estimated by the proposed algebraic equations coincide fairly well with those of finite element method.

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