• Title/Summary/Keyword: static component-dominated beam

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Finite element formulation and analysis of Timoshenko beam excited by transversely fluctuating supports due to a real seismic wave

  • Kim, Yong-Woo;Cha, Seung Chan
    • Nuclear Engineering and Technology
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    • v.50 no.6
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    • pp.971-980
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    • 2018
  • Using the concept of quasi-static decomposition and using three-noded isoparametric locking-free element, this article presents a formulation of the finite element method for Timoshenko beam subjected to spatially different time-dependent motions at supports. To verify the validity of the formulation, three fixed-hinged beams excited by the real seismic motions are examined; one is a slender beam, another is a stocky one, and the other is an intermediate one. The numerical results of time histories of motions of the three beams are compared with corresponding analytical solutions. The internal loads such as bending moment and shearing force at a specific time are also compared with analytic solutions. These comparisons show good agreements. The comparisons between static components of the internal loads and the corresponding total internal loads show that the static components predominate in the stocky beam, whereas the dynamic components predominate in the slender one. Thus, the total internal loads of the stocky beam, which is governed by static components, can be predicted simply by static analysis. Careful numerical experiments indicate that the fundamental frequency of a beam can be used as a parameter identifying such a stocky beam.

Analytic solution of Timoshenko beam excited by real seismic support motions

  • Kim, Yong-Woo
    • Structural Engineering and Mechanics
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    • v.62 no.2
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    • pp.247-258
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    • 2017
  • Beam-like structures such as bridge, high building and tower, pipes, flexible connecting rods and some robotic manipulators are often excited by support motions. These structures are important in machines and structures. So, this study proposes an analytic method to accurately predict the dynamic behaviors of the structures during support motions or an earthquake. Using Timoshenko beam theory which is valid even for non-slender beams and for high-frequency responses, the analytic responses of fixed-fixed beams subjected to a real seismic motions at supports are illustrated to show the principled approach to the proposed method. The responses of a slender beam obtained by using Timoshenko beam theory are compared with the solutions based on Euler-Bernoulli beam theory to validate the correctness of the proposed method. The dynamic analysis for the fixed-fixed beam subjected to support motions gives useful information to develop an understanding of the structural behavior of the beam. The bending moment and the shear force of a slender beam are governed by dynamic components while those of a stocky beam are governed by static components. Especially, the maximal magnitudes of the bending moment and the shear force of the thick beam are proportional to the difference of support displacements and they are influenced by the seismic wave velocity.

Effects of Four Sides Constraint for Shear Strength of ${\sharp}$ Shape Double Beam-Column Connections (정(${\sharp}$)자형 더블보-기둥 접합부의 전단강도에 대한 4변 구속의 영향)

  • Kim, Lyang-Woon;Chung, Chang-Yong;Lee, Soo-Kueon;Kim, Sang-Sik;Choi, Kwang-Ho;Lee, Jung-Yoon
    • Proceedings of the Korea Concrete Institute Conference
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    • 2008.04a
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    • pp.209-212
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    • 2008
  • DBS method of underground works can reduce the term of works for manufacturing the underground members in factory and producing members in modularization, apart from that, the horizontal member could be used as permanent members, which are the advantages of this method. As the component element of DBS method, in order th transfer the vertical load on horizontal member to the column during the construction or in service, developed ${\sharp}$ shaped double beam-column connection is dominated by shear failure in the complicated state of multi-axial stresses. In this study, in order to check the shear-failure mechanism of ${\sharp}$ shaped connection of double beam-column and an increase of shear internal force with the thickness of the steel plate. 7 specimens were made and one-way static tests. All of the specimens were subjected to brittle failure. Constraint of slab will increase its shear strength by 1.06${\sim}$1.48 times. Shear strength of slabs with different constraints steel plate in two-way increase more than which are same. So the slab with different constraints steel plate will be more effective.

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