• Title/Summary/Keyword: integral solution

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A two dimensional mixed boundary-value problem in a viscoelastic medium

  • Ataoglu, S.
    • Structural Engineering and Mechanics
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    • v.32 no.3
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    • pp.407-427
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    • 2009
  • A fundamental solution for the transient, quasi-static, plane problems of linear viscoelasticity is introduced for a specific material. An integral equation has been found for any problem as a result of dynamic reciprocal identity which is written between this fundamental solution and the problem to be solved. The formulation is valid for the first, second and mixed boundary-value problems. This integral equation has been solved by BEM and algorithm of the BEM solution is explained on a sample, mixed boundary-value problem. The forms of time-displacement curves coincide with literature while time-surface traction curves being quite different in the results. The formulation does not have any singularity. Generalized functions and the integrals of them are used in a different form.

Derivation of an Asymptotic solution for a Perfect Conducting Wedge by Using the Dual Integral Equation, Part II : H-Polarized Plane Wave Incidence (쌍적분 방정식을 이용한 완전도체쐐기의 점근해 유도, II : H-분극된 평면파 입사시)

  • Ha, Huen-Tae;Ra, Jung-Woong
    • Journal of the Korean Institute of Telematics and Electronics D
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    • v.36D no.1
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    • pp.22-28
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    • 1999
  • An exact asymptotic solution for a perfect conducting wedge with H-polarized plane wave incidence is analytically derived by substituting the exact boundary fields of the perfeet conducting wedge, the well known series solution, into the dual integral exquation in the spectral domain. The validity of the derivation is assured by showing that the analytic integration gives the null fields in the complementary region. The merits taking the dual integral equation for derivation of an asymptotic solution for a perfect conduction wedge is discussed.

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ON A DISCUSSION OF NONLINEAR INTEGRAL EQUATION OF TYPE VOLTERRA-HAMMERSTEIN

  • El-Borai, M.M.;Abdou, M.A.;El-Kojok, M.M.
    • The Pure and Applied Mathematics
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    • v.15 no.1
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    • pp.1-17
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    • 2008
  • Here, we consider the existence and uniqueness solution of nonlinear integral equation of the second kind of type Volterra-Hammerstein. Also, the normality and continuity of the integral operator are discussed. A numerical method is used to obtain a system of nonlinear integral equations in position. The solution is obtained, and many applications in one, two and three dimensionals are considered.

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USING CROOKED LINES FOR THE HIGHER ACCURACY IN SYSTEM OF INTEGRAL EQUATIONS

  • Hashemiparast, S.M.;Sabzevari, M.;Fallahgoul, H.
    • Journal of applied mathematics & informatics
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    • v.29 no.1_2
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    • pp.145-159
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    • 2011
  • The numerical solution to the linear and nonlinear and linear system of Fredholm and Volterra integral equations of the second kind are investigated. We have used crooked lines which includ the nodes specified by modified rationalized Haar functions. This method differs from using nominal Haar or Walsh wavelets. The accuracy of the solution is improved and the simplicity of the method of using nominal Haar functions is preserved. In this paper, the crooked lines with unknown coefficients under the specified conditions change the system of integral equations to a system of equations. By solving this system the unknowns are obtained and the crooked lines are determined. Finally, error analysis of the procedure are considered and this procedure is applied to the numerical examples, which illustrate the accuracy and simplicity of this method in comparison with the methods proposed by these authors.

입계기공의 확산성장 모델을 이용한 고온 기기의 크립균열전파 해석 (2)

  • Jeon, Jae-Young
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.20 no.4
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    • pp.1186-1193
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    • 1996
  • The analytic solution of the stress field at creep crack in the presence of grain boundary caviation is to be obtained by solving the governing equation which was derived through the previous paper. The complex integral technique is used to slove the singular integral equation. under the help of the information about stress behaviors at the ends of integral region know by numerical solution. The resultant stress disstribution obtained shows the relaxed crack-tip singularity of $r^{1/2+\theta}$ due to the intervention of cavitation effect, otherwise, it should assumed to be $r^{1/2}$ singularity of linear elastic fracture mechanics with no cavitation.

Flapwise and non-local bending vibration of the rotating beams

  • Mohammadnejad, Mehrdad;Saffari, Hamed
    • Structural Engineering and Mechanics
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    • v.72 no.2
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    • pp.229-244
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    • 2019
  • Weak form integral equations are developed to investigate the flapwise bending vibration of the rotating beams. Rayleigh and Eringen nonlocal elasticity theories are used to investigate the rotatory inertia and Size-dependency effects on the flapwise bending vibration of the rotating cantilever beams, respectively. Through repetitive integrations, the governing partial differential equations are converted into weak form integral equations. The novelty of the presented approach is the approximation of the mode shape function by a power series which converts the equations into solvable one. Substitution of the power series into weak form integral equations results in a system of linear algebraic equations. The natural frequencies are determined by calculation of the non-trivial solution for resulting system of equations. Accuracy of the proposed method is verified through several numerical examples, in which the influence of the geometry properties, rotatory inertia, rotational speed, taper ratio and size-dependency are investigated on the natural frequencies of the rotating beam. Application of the weak form integral equations has made the solution simpler and shorter in the mathematical process. Presented relations can be used to obtain a close-form solution for quick calculation of the first five natural frequencies of the beams with flapwise vibration and non-local effects. The analysis results are compared with those obtained from other available published references.

Dynamic Behaviors of an Impact System under Randomly Perturbed Harmonic Excitation by the Path-Integral Solution Procedure (Path-Integral Solution을 이용한 랜덤동요된 조화가진력을 받는 임팩트시스템의 거동분석)

  • 마호성
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.17 no.1
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    • pp.83-91
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    • 2004
  • Nonlinear system responses of an impact system under randomly perturbed harmonic excitations are predicted in the probability domain by adopting the semi-analytical procedure previously developed. The semi-analytical procedure is obtained by solving the Fokker-Planck equation corresponding to the stochastic differential equation of the given impact system by utilizing the path-integral solution. The evolutionary joint probability density functions are generated by using the method, and the characteristics of nonlinear dynamic response behaviors of the system are examined. Noise effects on the responses are also examined. It Is found that the semi-analytical method can provides the accurate information of the responses via the joint probability functions for the impact system. It is found that the noises weaken and eventually terminate the chaos in the responses, but it is also found that the chaotic signatures reside in the presence of the external noise with relatively high intensity. The joint probability density function shows that the ensemble of the system responses are weakly stationary.

A Numerical Method for the Minimum Norm Solution to the First Kind Integral Equations

  • Yun, Jae Heon
    • Journal of the Chungcheong Mathematical Society
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    • v.6 no.1
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    • pp.25-43
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    • 1993
  • This paper introduces a numerical method approximating the minimum norm solution to the first kind integral equation Kf = g with its kernel satisfying a certain property, where g belongs to the range space of K. Most of the existing expansion methods suffer from choosing a set of basis functions, whereas this method automatically provides an optimal set of basis functions approximating the minimum norm solution of Kf = g. Perturbation results and numerical experiments are also provided to analyze this method.

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