• 제목/요약/키워드: Theoretical

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단순 Box형 Cut-out 차체모델의 경량화를 위한 이론적 개념설계 모델 연구 (A Study on a Theoretical Conceptual Design Model to Reduce the Weight of a Simple Box-type Cut-out Carbody)

  • 조정길;구정서;정현승
    • 한국철도학회:학술대회논문집
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    • 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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    • pp.2666-2671
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    • 2011
  • In this paper, a theoretical approach was studied to make a baseline box type model satisfying the stiffness condition of a cut-out model. First, we compared the sum of the sectional theoretical deflections and the FEM result of the cut-out model under the static load test conditions, and we obtained good correlations from both the results. Second, To obtain the thickness of the baseline model, we used the mean value of geometric moment of intertia of the side wall and roof structure. Also, we compared the theoretical results and the FEM result of a baseline model, and we obtained good correlations. It is considered that the developed theoretical approach can be used for the weight reduction of train carbodies.

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이론적 방법에 의한 제습로터 최적 회전속도의 결정 (Theoretical Derivation of the Optimum Rotation Speed of a Desiccant Rotor)

  • 이대영;송귀은
    • 설비공학논문집
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    • 제21권10호
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    • pp.575-582
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    • 2009
  • The optimum rotation speed of a desiccant rotor is studied theoretically based on a theoretical solution to the heat and mass transfer processes in the desiccant rotor. A simple correlation equation for the optimum rotation speed is derived to show the effects of various parameters including the thermo-physical properties, the geometric dimension, and the operating condition of the desiccant rotor. The theoretical result is compared with existing experimental data to validate the linearization and simplification included in the solution procedure. Based on the theoretical solution, the effects of major parameters on the optimum rotation speed are studied and the fundamental mechanism of the influences is investigated.

Theoretical substruction : 심부정맥 환자의 피로감 (Theoretical Substruction: Fatigue in Cardiac Arrhythmia Patients)

  • 강윤희
    • 기본간호학회지
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    • 제8권3호
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    • pp.430-437
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    • 2001
  • 모든 질병에서 피로감은 환자가 경험하는 매우 흔한 증상으로서 임상간호현장에서 쉽게 간과 되어져왔다. 최근까지 건강관련 학문분야에서 피로감에 관한 수많은 연구가 진행되어져 왔지만. 임상간호현장에 도움이 될 만한 연구결과, 즉 임상 간호사의 간호사정과 간호중재에 지침이 되는 연구는 부족한 현실이다. 구체적인 연구 계획에 앞서, 연구의 이론적인 배경과 근거, 이론에서 추출된 개념, 변수와 연구 도구들간의 전체적인 일관성이 매우 중요하다. 추상적인 이론으로부터 개념과 변수를 거쳐 연구에 직접 사용될 구체적인 연구도구를 일관성 있게 선택하는 일련의 과정을 'Theoretical Substruction'이라 한다. 심부정맥환자가 지각하는 피로감에 관한 연구에 앞서, 본 글을 통해 심부정맥과 피로감의 이론적인 연관성과 이 연구를 위한 개념과 변수, 구체적인 연구도구를 선택하는 과정, Theoretical Substruction에 대해 토의될 것이며, 이에 따른 연구질문도 제의 될 것이다.

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표면 손상을 입은 적층판의 강도 예측 및 분석 (Prediction and Analysis of Fracture Strength for Surface Flawed Laminates)

  • 최덕현;황운봉
    • 한국복합재료학회:학술대회논문집
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    • 한국복합재료학회 2004년도 춘계학술발표대회 논문집
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    • pp.275-278
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    • 2004
  • In this paper, the fracture strength of the surface damaged laminates was predicted by applying the fracture strengths of the unflawed and flawed laminates. For prediction, the theoretical equation about the fracture strength of laminates was simplified applying classical laminate theory and was applied to the surface damaged laminates. Lagace's and Tsai's experimental data were used for verifying the theoretical equation. Moreover, to verify the theoretical prediction, an experiment was performed. Surface unflawed laminate and flawed laminates were fabricated and the experiments were made and these results were compared with theoretical predictions. The specimens' fiber direction was same to the tensile direction and the theoretical predictions and the experimental results were showed good agreement. Therefore, by this equation, the fracture strength of structures made of composites will be able to be predicted when the surface of the structures was damaged.

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Stress analysis of a new steel-concrete composite I-girder

  • Wang, Yamin;Shao, Yongbo
    • Steel and Composite Structures
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    • 제28권1호
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    • pp.51-61
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    • 2018
  • A new I-girder consisted of top concrete-filled tubular flange and corrugated web has been proved to have high resistance to both global buckling of the entire girder and local buckling of the web. This study carries out theoretical analysis and experimental tests for this new I-girder to investigate the stress distribution in the flanges and in the corrugated web. Based on some reasonable assumptions, theoretical equations for calculating the normal stress in the flanges and the shear stress in the corrugated web are presented. To verify the accuracy of the presented equations, experimental tests on two specimens were carried out, and the experimental results of stress distribution were used to assess the theoretical prediction. Comparison between the two results indicates that the presented theoretical equations have enough accuracy for calculating the stress in the new I-girder, and thus they can be used reliably in the design stage.

일 뇌졸중 이차예방프로그램 논문의 분석 및 평가 (Analysis and Evaluation of a Nursing Research Paper on Secondary Prevention Program for Stroke)

  • 서은희;박선일
    • 한국농촌간호학회지
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    • 제5권1호
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    • pp.16-24
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    • 2010
  • Nursing theory is used to explain the goals and functions of nursing and improve practical affairs by providing information and knowledge about the principles which become the foundation of nursing practical affairs. Theoretical analytical compliance with C-T-E (Conceptual-Theoretical-Empirical) structures by Fawcett (1999) whose evaluation method illustrates the relationship of conceptual models, theory, research and structure. The evaluation allows the nurse to visualize the connection, evaluate research, and reduce errors in research. Consequently present doctorate dissertations in nursing science are theoretical propriety, connection in the structure of concepts, theory, research methods, and evaluation to reduce errors in future research plans and division of theoretical development process. So the following verifies logicality, propriety, and reliability which must apply to research in various different fields.

에너지기술의 학습 효과에 대한 이론적 고찰 (A Theoretical Review on the Experience Curve toy Energy Technology)

  • 장한수;최기련
    • 에너지공학
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    • 제15권4호
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    • pp.209-228
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    • 2006
  • 학습효과는 에너지기술의 전개와 관련된 메커니즘을 규명하려는 이론 중 하나이다. 본 논문에서는 학습 효과에 대한 이론적 고찰을 함으로써 아직까지는 국내에서 일천한 관련 이론에 대한 기반을 제공하고자 한다. 이를 위하여 학습곡선과 관련된 국내외 선행연구사례, 제반이론, 적용방법 및 정책 응용에 관하여 살펴본다. 또한 에너지기술의 학습과 비용절감 요인에 대하여 살펴봄으로써 학습곡선의 메커니즘을 파악한다. 마지막으로 각 장별 내용을 바탕으로 결론을 도출한다.

Vortex-induced oscillations of bridges: theoretical linkages between sectional model tests and full bridge responses

  • Zhang, Zhitian;Ge, Yaojun;Chen, Zhengqing
    • Wind and Structures
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    • 제19권3호
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    • pp.233-247
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    • 2014
  • Vortex-induced oscillation is a type of aeroelastic phenomenon, to which extended structures such as long-span bridges are most susceptible. The vortex-induced vibration (VIV) behaviors of a concerned bridge were investigated conventionally in virtue of wind tunnel tests on string-mounted sectional models. This necessitates the building of a linkage between the response of the sectional model and that of the prototype structure. Although many released literatures have related to this issue and provided suggestions, there is a lack of consistency among them. In this study, some theoretical models describing the vortex-induced structural motion, including the linear empirical model, the nonlinear empirical model and the modified (or generalized) nonlinear empirical model, are firstly reviewed. Then, the concept of equivalent mass density is introduced based on the principle that an equal input of energy should result in identical structural amplitudes. Based on these, the theoretical linkages between the amplitude of a section model and that corresponding to the prototype bridge are discussed with different analytical models. Theoretical derivation indicates that such connections are dependent mainly on two factors, one is the presupposed shape of deformation, and the other is the theoretical VIV model employed. The theoretical analysis in this study shows that, in comparison to the nonlinear empirical models, the linear one can result in obvious larger estimations of the full bridges' responses, especially in cases of cable-stayed bridges.