• Title/Summary/Keyword: cross section shape

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Modal Characteristic Optimization of Rotating Cantilever Beams via Shape Variation of Cross-section by Multi-stage Spline Function (다단 Spline 곡선에 의한 단면형상 변화를 통한 회전 외팔보의 진동특성 최적화)

  • 조정은;유홍희
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2003.11a
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    • pp.684-689
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    • 2003
  • When structures undergo rotating motion, their modal characteristics often vary significantly. The variations of modal characteristics are determined from their geometric shapes and their rotating angular speed. Since the modal characteristics vary during the operation of the structures, they should be carefully scrutinized. In this paper, rotating cantilever beams are chosen as design targets which need to meet some specific design requirements. The thickness and the width of the rotating beams are assumed as multi-stage spline functions and the stage values for the thickness and the width are used as design variables for the optimization problems.

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The Characteristics of Silk Sericin/polyurethane Mixed Film (견 세리신/폴리우레탄 혼합필름의 특성)

  • 김문정;배도규
    • Journal of Sericultural and Entomological Science
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    • v.40 no.2
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    • pp.143-149
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    • 1998
  • For the application of silk sericin, silk sericin powders were prepared by various spray dry conditions and the characteristics of silk sericin/polyurethane mixed films were investigated. When the sericin was dried from the solution at higher inlet and outlet temperature, larger sizes of the powder particles were obtained. It was also found that inlet and outlet temperatures were important factors affecting the shape and surface characteristics of sericin power particle. The many holes and empty spaces were observed at the surface and cross section of sericin/PU mixed film. With the increase of the amount of sericin powder in the mixed films, the size and number of holes and empty spaces were increased. The thickness of sericin/PU mixed film was increased with the content of sericin powder. As the portion of sericin powder increase, the tenacity is decreased while the elongation slightly increased.

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A Vibration Analysis Model for Bellows in the Vehicle Exhaust System Using Method of Reduced Degree of Freedom (자유도 저감법을 이용한 자동차 배기시스템의 벨로우즈 진동해석)

  • Shim, Dong-Hyouk;Kim, Dae-Hyun;Choi, Myung-Jin
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2006.05a
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    • pp.304-308
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    • 2006
  • The focus of this study is modeling technique for a bellows in vehicle exhaust system. Bellows was developed using tile finite element model by replacing with the equivalent beam. The equivalent beam model were studied in detail. Non-structural node in the cross section of original model is given to expressing their motion. Equivalent mass matrix and stiffness matrix calculated using Guyan reduction method. Material Properties of beam was obtained from the direct comparison between equivalent model and that of Timoshenko beam model. The calculated natural frequencies and mode shape are compared with the reference results and coincided well. The results were compared with the confirmed results, which were in good agreement.

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Flow Routing in Prismatic Symmetrical Compound Channels by Applications of the Apparent Shear Force (ASF)

  • Chun, Moo-Kap;Jee, Hong-Kee
    • Korean Journal of Hydrosciences
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    • v.8
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    • pp.41-56
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    • 1997
  • A new routing computer model for the symmetric compound channel called the ASRMCS(Apparent Shear Force Muskingum-Cunge Method in Symmetry) has been developed. The Muskingum-Cunge routing method is adapted. The Apparent Shear Force (ASF) between the deep main channel and the shallow floodplan flow is introduced while the flow is routed. The nonlinear parameter method is applied. The temporal and spatial increments are varied according to the flow rate. The adaptation of above schemes is tested against the routed hydrographs using the DAMBRK model. The results of general routing practice of Muskingum-Cunge Method(GPMC) are also compared with those of above two models. The results of the new model match remarkably well with those of DAMBRK. The routed hydrographs show a smooth variation from the inflow boundary condition without any distortions caused by the difference of cross-section shape. However, the results of GPMC, showing early rise and fall of routed hydrograph, have considerable differences from those of the ASFMCS and DAMBRK.

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Development of Functional Sports-brassiere (기능적 Sports-brassiere 개발에 관한 연구)

  • 최혜선;손부현
    • Journal of the Korean Society of Clothing and Textiles
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    • v.20 no.3
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    • pp.452-466
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    • 1996
  • The purpose of this study is to proviede basic data for designing sports-brassiere by a questionnaire survey about sports-brassieres preferences and physiological wearing test. The results of the survey and the physiological wearing tests on sports-brassieres are as follow; 1. According to the survey, dissatisfied factors on the sports-brassiere are "drooping and vibrating of the breasts". Preferable factors are supporting breasts by stretch and seldom changing its position by motion. The bigger cup-size and more hemispherical-type causes more discontent than flat-type. 2. The shape of breasts is oval, on what ground, horizontal line is longer than vertical. For the cross section of bust line, shirts type.brassiere is more gently curved than cup-brassiere. 3. The feeling of wearing comfort is correlated with bust.up, shield, close adhesion. The vibration of breasts is correlated with covering urea and close adhesion, and the changing band's position by movement, close adhesion. Too much covering area or strain are in inverse correlation of the comfort. 4. The rate of prevention of vibration is 75~80% on superior sports-brassieres, which has broad covering area and excellent close adhesion. adhesion.

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The Crush Energy Absorption Capacity Optimization for the Side-Member of an Aluminum Space Frame Vehicle (알루미늄 차체의 사이드멤버 충돌에너지 흡수성능 최적설계)

  • 김정호;김범진;허승진;김민수
    • Transactions of the Korean Society of Automotive Engineers
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    • v.12 no.5
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    • pp.94-100
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    • 2004
  • In order to improve the frontal crash performance of an Aluminum Space Frame Vehicle, this presents a systematic optimal design process to maximize the crush energy absorption capacity of side-members while satisfying the maximum displacement constraint. In this study, five design types are studied for selecting a good collapse initiator. Then, for the selected collapse initiator type, 7 design variables are defined to represent cross section shape, thickness and bead interval. The systematic optimization processor, R-INOPL uses DOE, RSM and numerical optimization techniques. R-INOPL uses only 14 analyses to solve the 7 design variable optimization problem the final design can improve 103.9% of the internal energy and reduce 13.9% of the maximum displacement.

Fabrication and Characterization of NbTi Superconduction wire for MRI (MRI용 NbTi 초전도선재 제조 및 초전도 특성 평가)

  • Ha, D.W.;Oh, S.S.;Ryu, K.S.;Han, I.Y.;Lee, C.K.
    • Proceedings of the KIEE Conference
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    • 1997.07d
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    • pp.1494-1496
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    • 1997
  • The MRI Magnet is a most practical application of NbTi superconductor. In this paper, we present the main research results on superconducting wires for MRI magnet which we have developed. Cu/NbTi superconducting wires were fabricated by repeat of cold working and heat-treating process after that billets were extruded. We investigated the relation of superconductivities of wires and heat treatment condition. The correlation between cross section shape of wires and work inhomogeneity of NbTi rods was investigated by microscopic observation. The more repeatation number of cold working and heat-treating process, the higher critical current is achieved.

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A theoretical study on the factors for the seismic performance of RC T-shaped walls (철근콘크리트 T형 벽체의 내진성능 영향인자에 관한 해석적 연구)

  • 하상수;최창식;오영훈;이리형
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2002.10a
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    • pp.521-526
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    • 2002
  • The seismic performance of structural walls subjected to the cyclic lateral loads are influenced by various factors, like sectional shape, aspect ratio, reinforcement ratio, arrangement of reinforcement, and axial load ratio etc. In this research, reinforced concrete structural walls with the T-shaped cross section were selected. The seismic performance of T-shaped wall was affected by the many (actors because T-shaped wall is irregular wall composed to two rectangular walls. Especially the seismic performance of T-shaped wall varies with the flange condition and the various factors including the flange condition were determined. Therefore, the objective of this study is to understand the factors to improve seismic performance of RC T-shaded tv using sectional analysis.

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A Study of Improving the Human Body for Koran Women -Centering around Body Production- (한국여성에 적합한 인대에 관한 연구 -인대 제작을 중심으로-)

  • Im, Soon
    • The Research Journal of the Costume Culture
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    • v.2 no.1
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    • pp.29-38
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    • 1994
  • This research has been to perform with various methods of measurement of human body. As experiment methods, performed the body measurement method with Martin's measurer, took pictures for he observation of body gesture and body shape, and applied the cross-section measurement method of each body part for the making of body pivot. In the making of body pivot. used several sheets of styroform, and attached some gypsum power on the surface of the body pivot for he body silhouette of body. Eventhough, there were not enough subjects for this study, these methods will be continuously conducted with enough subjects, there will be to develop the body measurement method for Korean women, and will find to solve a suitable manufacturing body and the study of body for Korean women.

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Analysis on Induced Current Density Inside Human Body by 60 Hz ELF Magnetic Fields (60Hz ELF 자계에 의한 인체내부 유도 전류밀도 해석)

  • Min Suk-Won;Song Ki-Hyun
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.55 no.2
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    • pp.76-81
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    • 2006
  • This paper analysed the characteristics of current density induced inside human body by 60 Hz extremely low frequency magnetic fields according to varying conductivities of human model. Human model was composed of several organs and other parts, whose shapes were expressed by spheroids or cylinders. Organs such as the brain, heart, lungs, liver and intestines were taken into account. Applying the boundary element method to the human model, we estimated effects on the induced current distribution due to differences of the organ conductivity and shape. We find organ conductivity influences most and a cross section area and a position of organ also gives effects.