• Title/Summary/Keyword: 뿔대

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The Study for the Various Methods for the Volume of Frustum of Pyramid (사각뿔대 부피를 구하는 다양한 방법에 대한 탐구)

  • Yoon, Dae-Won;Kim, Dong-Keun
    • Journal for History of Mathematics
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    • v.23 no.3
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    • pp.91-106
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    • 2010
  • This is the study for various methods for getting the volume of frustum of pyramid. This study will first deal with how the formula of getting the volume of frustum of pyramid has been changed in the history of Mathematics. Secondly, based on the study of 'Prasolov' this study will deal with the calculation method for the volume of frustum of pyramid which was written in the 14th question of 'Moscow Papyrus' and search for the rules of solution for frustum of pyramid in the middle school textbooks. Finally, this study will consider various solutions for the volume of frustum of pyramid and its generalization.

Structural Optimization of Industrial Safety Helmet According to Frame Shape using Engineering Plastic (엔지니어링 플라스틱 소재별 보강뿔대 형상에 따른 산업용 안전모의 구조 최적화)

  • Park, Man-Ho;Lee, Yeo-Wool;Lee, Yong-Moon;Park, Jae-Ha;Kang, Myungchang
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.18 no.3
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    • pp.41-48
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    • 2019
  • The industrial safety helmets are personal protective equipment (PPE), used to protect the head against falls from a height. This study indicated the necessity of wearing a safety helmet while working at heights below 4 m, through analysis of fall accidents occurring in the industrial field. The stress, displacement, and strain of the safety helmet shell structure have been analyzed using the finite element method with various thicknesses, engineering plastics, and designs. It was preferred that the safety helmet shell structure had a reinforcement frame of uniform thickness in terms of increased impact strength and strain energy absorption rate. The thickness can be reduced to lighten the total weight for workers wearing safety helmets.

Topology Optimization of Offshore Wind-Power Turbine Substructure Using 3D Solid-Element Model (3 차원 고체요소모델을 활용한 해상풍력터빈 하부구조의 위상최적화)

  • Kim, Won Cheol;Chung, Tae Jin
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.38 no.3
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    • pp.309-314
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    • 2014
  • The structural layout of mechanical and civil structures is commonly obtained using conventional methods. For example, the shape of structures such as electric transmission towers and offshore substructures can be generated systematically. However, with rapid advancements in computer graphic technology, advanced structural analyses and optimum design technologies have been implemented. In this study, the structural shape of a jacket substructure for an offshore wind turbine is investigated using a topology optimization technique. The structure is subjected to multiple loads that are intended to simulate the loading conditions during actual operation. The optimization objective function is defined as one that ensures compliance of the structure under the given boundary conditions. Optimization is carried out with constraints on the natural frequency in addition to the volume constraint. The result of a first step model provides quick insights into the optimum layout for the second step structure. Subsequently, a 3D model in the form of the frustum of a quadrilateral pyramid is developed through topology optimization.