• Title/Summary/Keyword: 이방성판

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A Study on the Design Criteria Relating to the Local Buckling of Pultruded FRP Structural Compression Members (펄트루젼 구조압축재의 국부좌굴 설계규준 개발에 관한 연구)

  • Joo, Hyung Joong;Lee, Seung Sik;Yoon, Soon Jong
    • Journal of Korean Society of Steel Construction
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    • v.18 no.5
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    • pp.597-606
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    • 2006
  • Since FRP materials have various advantages over steel, many research activities to use them for the civil engineering applications are now in progress. The present paper deals with the local buckling behavior of FRP pultruded members as a first step toward the development of design criteria. In the design of compression members, it is very important to know not only if local buckling occurs or not but also which plate component governs local buckling, but it is not easy to perform this work in a rigorous manner. In the present paper, a simple and accurate equation which can compute the coefficients of buckling of orthotropic plates and local buckling of pultruded compression members is suggested by performing rigorous analysis, energy analysis, and parametric study. The local buckling strength and the plate component governing the local buckling behavior of thin-walled pultruded compression members can be easily determined by using the proposed equation.

Failure Strength Analysis of Simply Supported Sandwich Slab Bridges made by Composite Materials (복합재료로 만들어진 단순지지 샌드위치 슬래브 교량의 파괴강도해석)

  • Han, Bong-Koo;Kim, Se-Won
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.11 no.1
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    • pp.77-84
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    • 2007
  • In this paper presented, a design method of sandwich slab bridge of simple supported made by composite materials. Many of the bridge systems, including the girders and cross-beams, and concrete decks behave as the special orthotropic plates. Such systems with sections, boundary conditions other than Navier or Levy solution types, or with irregular cross sections, analytical solution is very difficult to obtain. Thus, Finite Difference Method is used for analysis of the pertinent problem. For the design of bridge made by the composite materials, cross-section is used the form-core shape because of this shape is economical and profitable, and for output of the stress value used F.D.M. Based the experimental of a composite specialist, an equation expressing the rate of decrease of tensile strength of glass fibers based on increase of mass was obtained. From these equations, one can estimate the rate of tensile strength reduction due to increased size. Tasi-Wu failure criterion for stress space is used. Strength-failure analysis procedure, using these reduced tensile strength, is presented.

Size Effects in the Failure of Simple Supported Sandwich Slab Bridges (단순지지된 샌드위치 슬래브교량의 파괴시 치수효과)

  • Han, Bong-Koo;Kim, Duck-Hyun
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.14 no.3
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    • pp.83-90
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    • 2010
  • Composite materials can be used economically and efficiently in civil engineering applications when standards and procedure for analysis, design, construction and quality control are to be established. Bridge systems, including the girders and cross-beams, and concrete decks behave as the specially orthotropic plates. For such systems with sections, boundary conditions other than Navier solution types, it is very difficult to obtain its analytical solution. To design the bridge made by the composite materials, cross-section was used as the form-core shape for economical reason and finite difference method was used for output of the stress value. The Tsai-Wu failure criterion for stress space is used. In this paper, the rate of tensile strength reduction due to increased size was considered. And also numerical study is made for these cases.

Vibration Analysis of Trapezoidal Corrugated Plates with Stiffeners and Lumped Masses (집중질량을 고려한 보강된 사다리꼴 주름판의 진동해석)

  • Jung, Kang;Kim, Young-Wann
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.24 no.5
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    • pp.414-420
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    • 2014
  • In this paper, the vibration characteristics of the trapezoidal corrugated plate with axial stiffeners and lumped masses are investigated by the analytical method. The corrugated plate can be treated as an equivalent orthotropic plate as this plate has different flexure properties in two perpendicular directions; flexible in the corrugation direction and stiff in the transverse direction. The effective extensional and flexural stiffness of the equivalent plate are considered to obtain the precise solution in the analysis. The plate is stiffened by concentric stiffeners horizontally to the corrugation direction. The discrete stiffener theory is adopted to consider the position of stiffener. To demonstrate the validity of the proposed approach, the comparison is made with the results of 3D ANSYS finite element solutions. Some numerical results are presented to check the effect of the geometric properties.

A Study on the Load Distribution Factor in the Perforated Square Plate with Elastic Support at Four Corners (彈性支持를 받는 四角多孔板의 荷重分布係數에 관한 연구)

  • 임정식;이영신
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.13 no.4
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    • pp.563-571
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    • 1989
  • The load distribution factor in the perforated square plate under concentrated load acting at arbitrary points through elastic media are calculated. For the calculation the perforated plate was converted into an orthotropic plate using the method suggested by J.B. Mahoney. In the process of the calculation the angle support at each corners was equivalent to a point support having equivalent stiffness. The deflections for the calculation of the load distribution factor were obtained using auxiliary plate extended in both directions of the plate and compared with the results from ANSYS calculations. After showing the validity of the current method, the calculation of the load distribution factor was performed. The result showed that the load distribution factor at the periphery of the plate is larger than that of in the central locations. This load distribution factor could be used for re-distribution of the applied load in more accurate analysis of the plate as well as it can be used in the analysis of the elastic media as the load factor.