• Title/Summary/Keyword: 굽힘 강성

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Static and Dynamic Analyses of Bending Problems Using 3-Dimensional 10-Node Equivalent Element (3차원 10절점-상당요소에 의한 굽힘문제의 정적.동적해석)

  • 권영두;윤태혁
    • Computational Structural Engineering
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    • v.10 no.4
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    • pp.117-130
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    • 1997
  • In this paper, a modified 10-node equivalent solid element(MQM10 element), which has smallest degrees of freedom among 3-dimensional solid elements accounting bending deformation as well as extensional and shear deformations of isotropic plates, is proposed. The proposed MQM10 element exhibits stiffer bending stiffness due to the reduction of degrees of freedom from 20-node element or Q11 element. As an effective way to correct the relative stiffness stiffening phenomenon, the modification equation of Gauss sampling points is proposed. The quantity of modification is a function of Poisson's ratio. The effectiveness of MQM10 element is tested by applying it to several examples. It is noted that the results of static and free vibration analysis of isotropic plates using MQM10 elements show a good agreement with those using 20-node element.

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Test Method for Composites Material Properties under High Temperature(I) (복합재의 고온 특성 평가를 위한 시험 기법연구(I))

  • Kil, Hyung-Bae;Yoon, Sung-Ho
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2012.05a
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    • pp.259-261
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    • 2012
  • The effect of high-temperature on the flexural modulus of epoxy resin were evaluated using universal testing machine with 3-point bending and dynamic mechanical analyzer. Temperatures of $30^{\circ}C$, $100^{\circ}C$, and $140^{\circ}C$ were considered for flexural test. The specimens having aspect ratio of 16, 32, and 40 were used. The results of storage modulus from DMA were similar to those from flexural test along with given temperatures. It is found that the flexural modulus increased with increasing aspect ratio and the specimen having aspect ratio of above 32 would be suitable for the evaluation of composite material properties under high temperature condition.

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Investigation into characteristics of bending stiffness and failure for ISB panel (ISB 판넬의 굽힘강성 및 파단특성에 관한 연구)

  • 안동규;이상훈;김민수;한길영;정창균;양동열
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2004.10a
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    • pp.1274-1277
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    • 2004
  • The objective of this research work is to investigate into characteristics of bending stiffness and failure for the ISB ultra-lightweight panel with internally structured material. The expanded metal with a pyramid shape and woven metal are employed as an internally structured material. In order to investigate the characteristics, the specific stiffness and failure map are estimated using the results of three-points bending test. From the results of the experiment, the influence of design parameters of ISB panel on the specific stiffness and failure mode has been found. In addition, it has been shown that ISB panel with expanded metal is prefer to that with woven metal from the view point of optimal design for ISB panel.

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The Effect of the Area Ratio and the Distance Ratio on Bending Stiffness of Two Rectangular Plates Spot-Welded (면적비와 거리비가 점용접된 두 사각평판의 굽힘강성에 미치는 영향)

  • Han, Geun-Jo;Ahn, Sung-Chan;Shim, Jae-Joon;Han, Dong-Seop
    • Proceedings of the KSME Conference
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    • 2001.11a
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    • pp.425-430
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    • 2001
  • The mechanical behavior of two rectangular plates spot-welded under bending is investigated in detail. The focus of the analysis is to evaluate the effect of thickness of reinforced plates with equivalent thickness. The results of this investigation are compared from detailed finite element analysis and experiments of the plates spot-welded for various parameters, such as aspect ratio, area ratio, and distance ratio of spot-welding points. The study is carried out using the equivalent thickness of the reinforced plates spot-welded.

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The Effect of the Area Ratio and the Distance Ratio on Bending Stiffness of Two Rectangular Spot-Welded Plates (면적비와 거리비가 점용접된 두 사각평판의 굽힘강성에 미치는 영향)

  • Han, Geun-Jo;Ahn, Sung-Chan;Shim, Jae-Joon;Han, Dong-Seop
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.27 no.3
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    • pp.387-392
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    • 2003
  • The mechanical behavior of two rectangular spot-welded plates under bending is investigated in detail. The equivalent thickness of spot-welded plates is introduced in this study and used in explaining the results. The focus of the analysis is to evaluate the effect of spot-welding from the view point of equivalent thickness. The investigation of deflection has been performed as comparing the result from finite element analysis with the measured data of the spot-welded plates for various parameters, such as aspect ratio, area ratio, and distance ratio of spot-welding points. The effect of spot-welding is as large as 62%(at r=1.0) when the area ratio of spot-welding point is just 4.52%.

Bending Vibration Analysis of Rotating Multi-blade Systems Considering the Coupling Stiffness Effect (연성강성 효과를 고려한 회전하는 다중 블레이드 시스템의 굽힘진동 해석)

  • Lim, Ha-Seong;Kwon, Sung-Hun;Yoo, Hong-Hee
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.16 no.9 s.114
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    • pp.912-918
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    • 2006
  • A modeling method for the vibration analysis of rotating multi-blade systems considering the coupling stiffness effect is presented in this paper. Blades are assumed as cantilever beams and the coupling stiffness effect originates from disc or shroud between blades. As the angular speed, hub radius ratio, and the coupling stiffness vary, the natural frequencies of the system vary. Numerical results show that the coupling stiffness is very important to estimate the natural frequencies. Along with the natural frequencies, associated mode shapes, critical angular speed, and critical hub radius ratio are obtained through the analysis.

Bending Vibration Analysis of Rotating Multi-blade Systems Considering the Coupling Stiffness Effect (연성강성 효과를 고려한 회전하는 다중 블레이드 시스템의 굽힘진동 해석)

  • Lim, Ha-Seong;Kwon, Sung-Hun;Yoo, Hong-Hee
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2006.05a
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    • pp.1354-1359
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    • 2006
  • A modeling method for the vibration analysis of rotating multi-blade systems considering the coupling stiffness effect is presented in this paper. Blades are assumed as cantilever beams and the coupling stiffness effect originates from disc or shroud between blades. As the angular speed, hub radius ratio, and the coupling stiffness vary, the natural frequencies of the system vary. Numerical results show that the coupling stiffness is very important to estimate the natural frequencies. Along with the natural frequencies, associated mode shapes, critical angular speed, and critical hub radius ratio are obtained through the analysis.

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Numerical Investigation of Surface Deformations in Resin Coated Quasi-Isotropic Laminates due to Thermal Variance (수지를 코팅한 준등방성 적층판에 대한 열변형 수치해석)

  • Kim, Kyung-Pyo
    • Korean Journal of Optics and Photonics
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    • v.25 no.4
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    • pp.207-215
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    • 2014
  • In this paper the radial stiffness associated with stacking sequence effects, and the dimensional stability issue associated with thermally induced surface deformation in quasi-isotropic laminates due to the effect of stacking sequence and additional resin layer technique, are numerically investigated. Finally, the influence of surface resin layer techniques for fiber print-through mitigation in a composite mirror is tested for evaluation of surface accuracy across varying thermal conditions.

Identification of Flexural Rigidity for Wire Rope Using Immune-Genetic Algorithm (면역-유전알고리즘에 의한 Wire Rope의 굽힘강성도 동정)

  • Choi, B.G.;Yang, B.S.;Kil, B.L.;Lee, S.J.
    • Journal of Power System Engineering
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    • v.2 no.1
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    • pp.52-58
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    • 1998
  • An immune system has powerful abilities such as memory, recognition and learning to respond to invading antigens, and is applied to many engineering algorithm recently. In this paper, the combined optimization algorithm is proposed for multi-objective problem by introducing the capability of the immune system that controls the proliferation of clones to the genetic algorithm. The optimizing ability of the proposed algorithm is identified by using multi-peak function which have many local optimums and identification of the flexural rigidity for wire rope model.

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Experimental Study on Dynamic Characteristics of Structurally Tailored Isotropic Box Beams (강성재단 된 등방성 박스보의 동적 특성에 관한 실험적 연구)

  • Kim, Kyoung-Duck;Kim, Jun-Sik
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.37 no.5
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    • pp.641-648
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    • 2013
  • A beam is a major load-carrying member in many engineering structures. Beams with properly designed cross sections and stiffeners are required to enhance the structural properties. Such a design may cause various coupling behaviors, and therefore, an accurate analysis is essential for the proper design of beams. In this research, we manufactured box-beams with stiffeners, which mimic the out-of-plane composite bending-shear coupling behavior reported in literature. A modal test is carried out to obtain the dynamic characteristics, such as natural frequencies and mode shapes, of the box-beam. The obtained results are compared with those of 3D FEM, which confirm that the out-of-plane bending-shear coupling behavior reported in literature is possible. The coupling behavior can be controlled by the proper design of the stiffeners.