• Title/Summary/Keyword: Cauchy's residue theorem

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A general closed-form solution to a Timoshenko beam on elastic foundation under moving harmonic line load

  • Luo, Wei-Li;Xia, Yong;Zhou, Xiao-Qing
    • Structural Engineering and Mechanics
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    • v.66 no.3
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    • pp.387-397
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    • 2018
  • In this paper, a general closed-form solution for evaluating the dynamic behavior of a Timoshenko beam on elastic foundation under a moving harmonic line load is formulated in the frequency-wavenumber domain and in a moving coordinate system. It is found that the characteristic equation is quartic with real coefficients only, and its poles can be presented explicitly. This enables the substitution of these poles into Cauchy's residue theorem, leading to the general closed-form solution. The solution can be reduced to seven existing closed-form solutions to different sub-problems and a new closed-form solution to the subproblem of a Timoshenko beam on an elastic foundation subjected to a moving quasi-static line load. Two examples are included to verify the solution.

Mean Square Response Analysis of the Tall Building to Hazard Fluctuating Wind Loads (재난변동풍하중을 받는 고층건물의 평균자승응해석)

  • Oh, Jong Seop;Hwang, Eui Jin;Ryu, Ji Hyeob
    • Journal of Korean Society of Disaster and Security
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    • v.6 no.3
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    • pp.1-8
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    • 2013
  • Based on random vibration theory, a procedure for calculating the dynamic response of the tall building to time-dependent random excitation is developed. In this paper, the fluctuating along- wind load is assumed as time-dependent random process described by the time-independent random process with deterministic function during a short duration of time. By deterministic function A(t)=1-exp($-{\beta}t$), the absolute value square of oscillatory function is represented from author's studies. The time-dependent random response spectral density is represented by using the absolute value square of oscillatory function and equivalent wind load spectrum of Solari. Especially, dynamic mean square response of the tall building subjected to fluctuating wind loads was derived as analysis function by the Cauchy's Integral Formula and Residue Theorem. As analysis examples, there were compared the numerical integral analytic results with the analysis fun. results by dynamic properties of the tall uilding.