• Title/Summary/Keyword: techno

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Direct frequency domain analysis of concrete arch dams based on FE-(FE-HE)-BE technique

  • Lotfi, Vahid
    • Computers and Concrete
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    • v.1 no.3
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    • pp.285-302
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    • 2004
  • A FE-(FE-HE)-BE procedure is presented for dynamic analysis of concrete arch dams. In this technique, dam body is discretized by solid finite elements, while the reservoir domain is considered by a combination of fluid finite elements and a three-dimensional fluid hyper-element. Furthermore, foundation rock domain is handled by three-dimensional boundary element formulation. Based on this method, a previously developed program is modified, and the response of Morrow Point arch dam is studied for various conditions. Moreover, the effects of canyon shape on response of dam, is also discussed.

Analysis of a cantilever bouncing against a stop according to Timoshenko beam theory

  • Tsai, Hsiang-Chuan;Wu, Ming-Kuen
    • Structural Engineering and Mechanics
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    • v.5 no.3
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    • pp.297-306
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    • 1997
  • The bouncing of a cantilever with the free end pressed against a stop can create high-frequency vibration that the Bernoulli-Euler beam theory is inadequate to solve. An analytic procedure is presented using Timoshenko beam theory to obtain the non-linear response of a cantilever supported by an elastic stop with clearance at the free end. Through a numerical example, the bouncing behavior of the Timoshenko and Bernoulli-Euler beam models are compared and discussed.

Saturation impulses for dynamically loaded structures with finite-deflections

  • Zhao, Ya-Pu;Yu, T.X.;Fang, J.
    • Structural Engineering and Mechanics
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    • v.3 no.6
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    • pp.583-592
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    • 1995
  • The concept of "Saturation Impulse" for rigid, perfectly plastic structures with finite-deflections subjected to dynamic loading was put forward by Zhao, Yu and Fang (1994a). This paper extends the concept of Saturation Impulse to the analysis of structures such as simply supported circular plates, simply supported and fully clamped square plates, and cylindrical shells subjected to rectangular pressure pulses in the medium load range. Both upper and lower bounds of nondimensional saturation impulses are presented.

Finite element modelling of reinforced concrete structures with laboratory verification

  • Cheng, Y.M.
    • Structural Engineering and Mechanics
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    • v.3 no.6
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    • pp.593-609
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    • 1995
  • The presence of reinforcement has a significant influence on the stress-strain behaviour of reinforced concrete structures, expecially when the failure stage of the structures is approached. In the present paper, the constrained and non-constrained zones of concrete due to the presence of reinforcement is developed and the stress-stress-strain behaviour of concrete is enhanced by a reinforcement confinement coefficient, Furthermore, a flexible method for the modelling of reinforcement with arbitrary orientation and not passing the nodes of concrete element is also proposed. Numerical examples and laboratory tests have shown that the coefficient and the modelling technique proposed by the author are satisfactory.

Inelastic buckling of tapered members with accumulated strain

  • Kim, M.C.;Lee, G.C.;Chang, K.C.
    • Structural Engineering and Mechanics
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    • v.3 no.6
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    • pp.611-622
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    • 1995
  • This paper is concerned with inelastic load carrying capacity of tapered steel members with or without accumulated plastic strains resulted from previous loading histories. A finite element program is developed using stiffness matrices of tapered members and is applicable for analyses with material and geometric nonlinearity. Results of analyses are compared with other available solutions and with experimental results.

Design curves for prestressed concrete rectangular beam sections based on BS 8110

  • Subramaniam, Kolluru V.L.;Sinha, S.N.
    • Structural Engineering and Mechanics
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    • v.3 no.6
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    • pp.555-567
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    • 1995
  • Design curves have been prepared for prestressed rectangular beam section based on BS 8110, for determining area of steel for any given cross section, for stresses in concrete and steel and for the design moment. The design moment and the area of steel have been expressed in dimensionless form in terms of cross sectional dimensions and the characteristic strength of concrete. The choice and combination of design parameters result in considerably less number of curves as aid for design of rectangular prestressed beam sections, than those reported in CP 110 (Part 3).

Structural Health Monitoring of short to medium span bridges in the United Kingdom

  • Brownjohn, James M.W.;Kripakaran, Prakash;Harvey, Bill;Kromanis, Rolands;Jones, Peter;Huseynov, Farhad
    • Structural Monitoring and Maintenance
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    • v.3 no.3
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    • pp.259-276
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    • 2016
  • Historically the UK has been a pioneer and early adopter of experimental investigation techniques on new and operation structures, a technology that would now be descried as 'structural health monitoring' (SHM), yet few of these investigations have been enduring or carried out on the long span or tall structures that feature in flagship SHM applications in the Far East.

The effect of sweep angle on the limit cycle oscillations of aircraft wings

  • Eken, Seher;Kaya, Metin Orhan
    • Advances in aircraft and spacecraft science
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    • v.2 no.2
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    • pp.199-215
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    • 2015
  • This study focuses on the limit cycle oscillations (LCOs) of cantilever swept-back wings containing a cubic nonlinearity in an incompressible flow. The governing aeroelastic equations of two degrees-of-freedom swept wings are derived through applying the strip theory and unsteady aerodynamics. In order to apply strip theory, mode shapes of the cantilever beam are used. The harmonic balance method is used to calculate the frequencies of LCOs. Linear flutter analysis is conducted for several values of sweep angles to obtain the flutter boundaries.

Generation of valley polarized current in graphene using quantum adiabatic pumping

  • Wang, Jing;Chan, K.S.
    • Advances in nano research
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    • v.3 no.1
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    • pp.39-47
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    • 2015
  • We study a device structure which can be used to generate pure valley current and valley polarized current using quantum adiabatic pumping. The design of the structure allows the flexibility of changing the structure from one for pure valley current generation to one for valley polarized current generation by changing the applied electric potentials through changing the symmetry of the structure. The device is useful for the development of valleytronic devices.

Revisiting exponential stress corrosion model

  • Elishakoff, Isaac;Miglis, Yohann
    • Ocean Systems Engineering
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    • v.1 no.2
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    • pp.121-130
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    • 2011
  • One of the prevailing models that describe the stress corrosion is represented by an exponential dependence between rate of corrosion and stress, suggested by Gutman, Zainullin and Zuripov. This study revisits the exponential model and derives analytical expressions for the structures' durability which is postulated as the time for stress level to reach its yield value. Comparison is conducted with other possible models, namely with linear, quadratic or cubic cases.