• Title/Summary/Keyword: 탄성판

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Elastic Shear Buckling Characteristics of Circularly Corrugated Plates (원형 파형 판의 탄성전단좌굴 특성)

  • Han, Taek Hee;Lim, Nam Hyoung;Park, Nam Hoi;Kang, Young Jong
    • Journal of Korean Society of Steel Construction
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    • v.14 no.4
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    • pp.529-538
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    • 2002
  • Applications of corrugated plates (or folded plates) have been recently increasing due to certain economic and structural advantages. Likewise, applications of corrugated plates has been increasing because they are stronger compared to flat plates. Therefore, specifications of corrugated plates should be determined. There are many design details in almost every specification for flat plates. However, except the bending strength and the normal strength, there are no detailed design guides such as shear strength. Thus, it is difficult for engineers to design structures consisting of corrugated plates. As such, engineers need a guide in designing corrugated plates. Extensive numerical study was conducted in order to identify the relationship between the shear strength and geometric conditions for corrugated plates. An eight-node thin shell element (QSL8) of the commercial program LUSAS (version 13.2) was used. The study was able to come up with a formula that helps determine the shear strength of corrugated plates under various geometric conditions, the size of corrugation, the curvature of corrugation, and the thickness of the corrugated plate. Likewise, corrugated plates were found to have a higher shear buckling strength than flat plates.

Free Vibrations and Strain Energy Anaylsis of Antisymmetric Cross-ply Laminted Plates (역대칭(逆対称) Cross-ply 다층판(多層板)의 자유진동(自由振動) 및 변형 에너지 해석(解釋))

  • Park, Moon Ho;Jin, Yoshimura;Takashi, Mikami;Park, Sung Jin
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.11 no.4
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    • pp.37-44
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    • 1991
  • A powerful analytical procedure and strain energy analysis to investigate the free vibration of antisymmetric cross-ply laminated plates, having one pair of opposite edges simply supported, are develped on the basis of the Yang, Norris abd Stavsky (YSN) theory. The equation of motion of the plate are solved by the use of collation method. A range of results are presented for plates to show the effects of modulus ratio and number of layers on natural frequency. In addition, an analysis of the strain energy distributions is used as an aid for the better understanding of the vibration characteristics of the plates.

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Elastic Interactive Shear Buckling Behavior of Trapezoidally Corrugated Steel Webs (제형파형강판 복부판의 탄성 연성전단좌굴 거동)

  • Yi, Jong Won;Gill, Heung Bae;Lee, Hak Eun
    • Journal of Korean Society of Steel Construction
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    • v.17 no.6 s.79
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    • pp.707-715
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    • 2005
  • Corrugated webs have been used for composite prestressed concrete box girder bridges. Innovative steel plate girders using corrugated webs have been proposed. It has been found that analytical and experimental researches conducted to determine the strength of trapezoidally corrugated webs can fail with respect to three different buckling modes: local, global, and interactive shear buckling. Shear buckling capacity equations based on classical and orthotropic plate buckling theories have been proposed,but these equations show some differences. In this paper, geometric parameters that influence interactive shear buckling behavior with interaction effects are identified via extensive bifurcation buckling analysis using the finite element meth.

Characterization of Thermal Expansion Coefficients of Carbon/Epoxy Composite for Temperature Variation (탄소섬유 복합재료의 온도변화에 대한 열팽창계수 특성 변화 규명)

  • 김주식;윤광준
    • Composites Research
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    • v.12 no.6
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    • pp.1-7
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    • 1999
  • The change of the coefficients of thermal expansion(CTE) of Carbon/Epoxy was investigated for the temperature variation and a prediction model for the change of CTE was proposed. Elastic properties and CTEs in the principal material directions were measured in the range of room temperature to cure temperature and characterized as functions of temperature. By applying the characterized properties to the classical lamination theory, a computational method to predict the change of CTEs of a general laminate for temperature variation was proposed. the coefficients of thermal expansion of laminates with various stacking sequences were measured and compared with those predicted. Good agreements between the predicted results and the experimental data show that the c hanges of CTEs of a general laminate for temperature variation can be predicted well by using the proposed method.

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A Study of the In-plane Rigidity of a Compressed Ship Plate above Buckling Load (압축하중을 받는 선체판의 좌굴후 면내강성에 관한 연구)

  • 고재용;박성현;박주신
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2002.11a
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    • pp.107-112
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    • 2002
  • Basically, ship structure consists of the plate members, and a strength of overall ship structurnds on the stiffness and strength of ship platings. If buckling which causes to deflect ship plate members occurs, the stiffness of ship plate markedly decreases, and thus buckling has a serious effect on the stiffness or strength of overall ship structure. Buckling is one of the most important design criteria when we scantle structure members. In the present study, a inplane rigidity of a compressed ship plate above buckling load is proposed. The proposed inplane rigidity is available in the elastic or elasto-Plastic ranges in order to can out a more efficient and reliable design.

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Elastic Local Buckling of Orthotropic Open Section Compression Members with Asymmetric Edge Stiffeners (비대칭 연단보강재가 설치된 직교이방성 개방단면 압축재의 탄성국부좌굴)

  • 윤순종;정상균
    • Composites Research
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    • v.14 no.4
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    • pp.1-7
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    • 2001
  • This paper presents the results of an analytical investigation pertaining to the elastic local buckling behavior of asymmetric edge stiffened orthotropic open section structural member under uniform compression. The asymmetric edge stiffener is considered as a beam element neglecting its torsional rigidity. We suggested the analytical model of asymmetric edge stiffeners which is composed of a strip of flange plate, equal width of edge stiffener, and a plate attached at the flange end, and computed the moment of inertia of the stiffener about an axis through the centroid of the ensuing cross-section. Using the derived equation, the local buckling coefficients of asymmetrically edge stiffened orhtotropic I-section columns are predicted and the results are presented in a graphical form.

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Evaluation of Tensile Properties of Carbon Fiber Reinforced Composite Laminates with Non-Woven Carbon Mat (부직포를 삽입한 탄소섬유강화 복합적층판의 인장특성 평가)

  • 정성균
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.6 no.4
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    • pp.96-100
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    • 1997
  • Tensile properties of carbon fiber reinforce composite laminates with non-woven carbon mat are evaluated in this paper. Composite laminates are made by inserting non-wovon carbon mat between layers, The specimens were cut and polished according to ASTM standard . Longitudinal and Transverse Young's modulus are obtained by tensile test. Young's moduli without non-woven carbon mat are compared with those with non-woven carbon mat. Longitudinal and Transverse tensile strength are also investigated. Experimental results show that the transverse Young's modulus of composite materials with non-woven carbon mat is about 10% higher than that of composite materials without non-woven carbon mat. Longitudinal tensile strength of composite materials with non-woven carbon mat is about 24% higher than that of composite materials without non-woven carbon mat. Transverse tensile strength and torughness also increase by inserting non-woven carbon mat between layers.

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Nitrogen Effect on Vertically Aligned CNT Growth (수직배향 CNT의 성장에 미치는 질소의 영향)

  • 김태영;오규환;정민재;이승철;이광렬
    • Journal of the Korean Vacuum Society
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    • v.12 no.1
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    • pp.70-77
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    • 2003
  • It is well Down that the growth of carbon nanotubes (CNTs) by chemical vapor deposition (CVD) using a transition metal catalyst is greatly enhanced in a nitrogen environment. We show here that the enhanced growth is closely related to the activated nitrogen and it's incorporation into the CNT wall and cap during growth. This behavior is consistent with theoretical calculations of CNx thin films, showing that nitrogen incorporation to the graphitic basal plane reduces the elastic strain energy for curving the graphitic layer. Enhanced CNT growth by nitrogen incorporation is thus due to a decrease in the activation energies required for nucleation and growth of the tubular graphitic layer.

Nonlinear Fracture Finite Element Model of Reinforced Concrete Plates (철근콘크리트판의 비선형 파괴 유한요소 모델에 관한 연구)

  • Jin, Chi Sub;Cha, Young Soo;Eom, Jong Uk
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.8 no.3
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    • pp.11-20
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    • 1988
  • A general finite element method is developed to analyze reinforced concrete plates under dead loads and monotonically increasing live loads. This method can be used to trace the load-deformation response and crack propagation through elastic, inelastic and ultimate ranges. The internal concrete and steel stresses can also be determined for any stage of the response history. A layered 8 node isoparametric element taking account of coupling effect between the membrane and the bending action is developed. An incremental tangent stiffness method is used to obtain a numerical solution. Validity of the method is studied by comparing the numerical solutions with other results.

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Analysis of Disc Degeneration in a Poroelastic Spinal Motion Segment FE Model (다공탄성체 척추운동분절 유한요소 모델을 이용한 추간판의 퇴화과정 분석)

  • Woo D.G.;Kim Y.E.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2005.10a
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    • pp.248-251
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    • 2005
  • To investigate the degeneration process in the intervertebral disc, a three dimensional (3D) poroelastic finite-element (FE) model was developed. Disc was modeled as two different regions, such as annulus modeled with fiber reinforced 20 node poroelastic ground matrix and nucleus having large porosity. Excess Von Mises stress in the disc element assumed to be a possible source of degeneration under compressive loading condition. Recursive calculation was continued until the desired convergence was attained by changing the permeability and porosity of those elements, which could be predicted from the previous iteration. The degenerated disc model showed that relatively small compressive stresses were generated in the nucleus elements compared to normal disc. Its distribution along the sagittal plane was matched well with a previously reported experimental result. Contrasts to this result, pore pressures in the nucleus were higher than those in the normal disc. Total stress indicated similar values for two different models. This new approach using poroelastic modeling could provide the explanation of the interaction between fluid and solid matrix in the disc during the degeneration process.

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