• Title/Summary/Keyword: coupling beam

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Multilayered viscoelastic beam loaded in torsion under strain-path control: A delamination analysis

  • Victor I. Rizov
    • Advances in materials Research
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    • v.13 no.2
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    • pp.87-102
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    • 2024
  • This paper is focused on the delamination analysis of a multilayered beam structure loaded in torsion under strain-path control. The beam under consideration has a rectangular cross-section. The layers of the beam are made of different viscoelastic materials which exhibit continuous inhomogeneity in longitudinal direction. Since the delamination is located inside the beam structure, the torsion moments in the two crack arms are obtained by modeling the beam as an internally static undetermined structure. The strain energy stored in the beam is analyzed in order to derive the strain energy release rate (SERR). Since the delamination is located inside the beam, the delamination has two tips. Thus, solutions of the SERR are obtained for both tips. The solutions are verified by analyzing the beam compliance. Delamination analysis with bending-torsion coupling is also performed. The solutions derived are timedependent due to two factors. First, the beam has viscoelastic behavior and, second, the angle of twist of the beam-free end induced by the external torsion moment changes with time according to a law that is fixed in advance.

Practical Design Method for Coupling Beams of Tall Buildings with Dual Frame System (이중골조형식 고층건물 커플링보의 실용설계)

  • Yoon, Tae-Ho;Kim, Jin-Sang
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.15 no.1
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    • pp.525-532
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    • 2014
  • In this study, practical design method of coupling beams is proposed. The member forces varies according to the location of the members and the members at 25%~40% of building height shows large member forces. The 100mm increase of wall thickness causes 3~4% variation of member forces and the 100MPa increase of concrete strength decrease approximately 3% of member forces. The required strength of coupling beams is twice the resistant strength and 80% reduction of coupling beam stiffness is necessary to fulfill the design criteria. The stiffness reduction of coupling beams is not necessary over the entire stories and the strength reduction range can be estimated considering design requirements.

Optimization of Optical Coupling Properties of Active-Passive Butt Joint Structure in InP-Based Ridge Waveguide (InP계 리지 도파로 구조에서 활성층-수동층 버트 조인트의 광결합 효율 최적화 연구)

  • Song, Yeon Su;Myeong, Gi-Hwan;Kim, In;Yu, Joon Sang;Ryu, Sang-Wan
    • Journal of the Microelectronics and Packaging Society
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    • v.27 no.4
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    • pp.47-54
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    • 2020
  • Integration of active and passive waveguides is an essential component of the photonic integrated circuit and its elements. Butt joint is one of the important technologies to accomplish it with significant advantages. However, it suffers from high optical loss at the butt joint junction and need of accurate process control to align both waveguides. In this study, we used beam propagation method to simulate an integrated device composed of a laser diode and spot size converter (SSC). Two SSCs with different mode properties were combined with laser waveguide and optical coupling efficiency was simulated. The SSC with larger near field mode showed lower coupling efficiency, however its far field pattern was narrower and more symmetric. Tapered passive waveguide was utilized for enhancing the coupling efficiency and tolerance of waveguide offset at the butt joint without degrading the far field pattern. With this technique, high optical coupling efficiency of 89.6% with narrow far field divergence angle of 16°×16° was obtained.

Cyclic behavior of steel beam-concrete wall connections with embedded steel columns (I): Experimental study

  • Li, Guo-Qiang;Gu, Fulin;Jiang, Jian;Sun, Feifei
    • Steel and Composite Structures
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    • v.23 no.4
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    • pp.399-408
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    • 2017
  • This paper experimentally studies the cyclic behavior of hybrid connections between steel coupling beams and concrete shear walls with embedded steel columns. Four beam-to-wall connection specimens with short and long embedded steel columns are tested under monotonic and cyclic loads, respectively. The influence of embedment length of columns on the failure mode and performance of connections is investigated. The results show that the length of embedded steel columns has significant effect on the failure mode of connections. A connection with a long embedded column has a better stiffness, load-bearing capacity and ductility than that of a short embedded column. The former fails due to the shear yielding of column web in the joint panel, while failure of the latter is initiated by the yielding of horizontal reinforcement in the wall due to the rigid rotation of the column. It is recommended that embedded steel columns should be placed along the entire height of shear walls to facilitate construction and enhance the ductility.

Electromagnetically-Induced-Absorption in Multiple-V type Atomic Systems (다중-V 타입 원자계에서의 전자기 유도 흡수)

  • Park, Jong-Dae;Cho, Chang-Ho;Lee, Chul-Se
    • The Journal of Natural Sciences
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    • v.12 no.1
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    • pp.41-48
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    • 2002
  • Atomic coherences can be induced via atom-light interaction and can exhibit new interesting phenomena. Electromagnetically-induced-absorption (EIA) is one of such phenomena where the absorption of probe beam is increased due to the presence of strong coupling beam. EIA can be observed in multiple-V type atomic systems. This paper present a method to study EIA when the frequencies of probe beam and coupling beam are both near resonant to the same transition line. Time-varying interaction Hamiltonian was introduced and density matrix equations were solved and the amplitude of oscillations was used to calculate the EIA.

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Experimental study on seismic performance of coupling beams not designed for ductility

  • Lam, S.S.E.;Wu, B.;Liu, Z.Q.;Wong, Y.L.
    • Structural Engineering and Mechanics
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    • v.28 no.3
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    • pp.317-334
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    • 2008
  • Seismic performance of coupling beams not designed for ductility is examined. Eight 1:4 scale coupling beam specimens, with seven reinforced concrete sections and one composite section, were tested under cycles of push-pull action. Characteristics of the specimens include moderate shear span ratio in the range of 2.5-3.5, high main reinforcement ratio at 3-4% and small to large stirrup spacing with 90- degree hooks. All the reinforced concrete specimens failed in a brittle manner. Displacement ductility of specimens with large stirrup spacing (${\geq}$140 mm) is in the range of 3 to 5. Seismic performance of the specimens is also examined using the ultimate drift angle and the amount of energy dissipated. Correlating the test data, an empirical relationship is proposed to estimate the ultimate drift angle of a class of coupling beams considered in the study not designed for ductility.

Exact vibration and buckling analyses of arbitrary gradation of nano-higher order rectangular beam

  • Heydari, Abbas
    • Steel and Composite Structures
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    • v.28 no.5
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    • pp.589-606
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    • 2018
  • The previous studies reflected the significant effect of neutral-axis position and coupling of in-plane and out-of-plane displacements on behavior of functionally graded (FG) nanobeams. In thin FG beam, this coupling can be eliminated by a proper choice of the reference axis. In shear deformable FG nanobeam, not only this coupling can't be eliminated but also the position of neutral-axis is dependent on through-thickness distribution of shear strain. For the first time, in this paper it is avoided to guess a shear strain shape function and the exact shape function and consequently the exact position of neutral axis for arbitrary gradation of higher order nanobeam are obtained. This paper presents new methodology based on differential transform and collocation methods to solve coupled partial differential equations of motion without any simplifications. Using exact position of neutral axis and higher order beam kinematics as well as satisfying equilibrium equations and traction-free conditions without shear correction factor requirement yields to better results in comparison to the previously published results in literature. The classical rule of mixture and Mori-Tanaka homogenization scheme are considered. The Eringen's nonlocal continuum theory is applied to capture the small scale effects. For the first time, the dependency of exact position of neutral axis on length to thickness ratio is investigated. The effects of small scale, length to thickness ratio, Poisson's ratio, inhomogeneity of materials and various end conditions on vibration and buckling of local and nonlocal FG beams are investigated. Moreover, the effect of axial load on natural frequencies of the first modes is examined. After degeneration of the governing equations, the exact new formulas for homogeneous nanobeams are computed.

Seismic Performance of Steel Coupling Beam and RC Shear Wall under Lateral Cyclic Load (주기하중 하에서 철근 콘크리트 전단벽체와 철골 연결보 접합부의 내진성능)

  • Lim, Woo-Young;Hong, Sung-Gul
    • Journal of the Korea Concrete Institute
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    • v.27 no.6
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    • pp.591-602
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    • 2015
  • In this paper, cyclic loading test was performed to evaluate the seismic performance of the steel coupling beam and RC shear wall. The test parameter was reinforcement detail of the shear wall. For the shear wall which was designed in accordance with the current design codes, a premature bearing failure occurred at the face of the wall. On the other hand, the bearing failure of walls was prevented due to the new type of reinforcement details. Test results indicated that the vertical reinforcements were more affected to the shear strength of the coupled shear wall than the horizontal reinforcement. Based on the failure mode, concrete stress distribution above and below flanges of the embedded steel beam was proposed. Assuming proposed concrete stress distribution, load resistance was predicted and it was agree well with test data.