• Title, Summary, Keyword: moving load

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A Study on the Dynamic Load Model of Truss Bridge subjected to Moving Train Loads (열차하중을 받는 트러스교의 동적하중모형 연구)

  • 안주옥;박상준
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • pp.111-118
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    • 1996
  • Dynamic load models which show the practical behavior of truss bridge subjected to moving train load are presented. Three basically approaches are available for evaluating structural response to dynamic effects : moving force, moving mass, and influence moving force and mass. Simple warren truss bridge model is selected in this research, and idealized lumped mass system, modelled as a planar structure. In the process of dynamic analysis, the uncoupled equation of motion is derived from simultaneous equation of the motion of truss bridge and moving train load. The solution of the uncoupled equations of motion is solved by Newmark-$\beta$ method. The results show that dynamic response of moving mass and static analysis considering the impact factor specified in the present railway bridge code was nearly the same. Generally, the dynamic response of moving force is somewhat greater than that of moving mass. The dynamic load models which are presented by this study are obtained relatively adequate load model when apply to a truss bridge.

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Fluid flow profile in the "orthotropic plate+compressible viscous fluid+rigid wall" system under the action of the moving load on the plate

  • Akbarov, Surkay D.;Huseynova, Tarana V.
    • Coupled systems mechanics
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    • v.9 no.3
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    • pp.289-309
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    • 2020
  • The paper studies the fluid flow profile contained between the orthotropic plate and rigid wall under the action of the moving load on the plate and main attention is focused on the fluid velocity profile in the load moving direction. It is assumed that the plate material is orthotropic one and the fluid is viscous and barotropic compressible. The plane-strain state in the plate and the plane flow of the fluid is considered. The motion of the plate is described by utilizing the exact equations of elastodynamics for anisotropic bodies, however, the flow of the fluid by utilizing the linearized Navier-Stokes equations. For the solution of the corresponding boundary value problem, the moving coordinate system associated with the moving load is introduced, after which the exponential Fourier transformation is employed with respect to the coordinate which indicates the distance of the material points from the moving load. The exact analytical expressions for the Fourier transforms of the sought values are obtained, the originals of which are determined numerically. Presented numerical results and their analyses are focused on the question of how the moving load acting on the face plane of the plate which is not in the contact with the fluid can cause the fluid flow and what type profile has this flow along the thickness direction of the strip filled by the fluid and, finally, how this profile changes ahead and behind with the distance of the moving load.

Modeling of the Structural Response of Pipes to Internal Blast Loading (관내 전파되는 파동에 대한 파이프의 구조적 반응에 대한 모델링)

  • Kim, Dae-Hyun;Yoh, Jai-Ick
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • pp.9-13
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    • 2008
  • The moving load such as a shock wave in a pipe propagates with a specific velocity. This internal load speed determines the level of flexural wave excitation and the possibility of resonant response leading to a large deformation. In this paper, we present particular solutions of displacements and the resonance conditions when the moving load is propagating in a pipe. These analytical results are compared to numerical simulations obtained using a hydrocode. We expect to identify potential explosion hazards in the general power industries.

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Vibration Characteristics of Continuous Beams Due to the Moving Loads with Constant Accelerations (一定加速度 의 移動荷重 이 作용하는 連續보 의 振動特性)

  • 김찬묵;김광식
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.6 no.4
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    • pp.323-330
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    • 1982
  • The vibration characteristics of continuous span periodically supported beams with moving loads are determined theoretically and experimentally. Moving loads are assumed to travel at constant acceleration with constant magnitude. Analyses by using the Fourier Transform technique are developed to determine the dynamic performance of moving load interacting with multiple and continuous beam. Equation of motion for the moving load is non-dimensionalized. Non-dimensional deflection proflies of continuous beam are presented in detail for the single concentrated moving load with constant acceleration. Experimental moving load and continuous beam models are developed. The maximum deflections at each midpoints 5,7 and 9 span beam are measured and their non-dimensional maximum deflections are presented. The non-dimensional maximum deflection of continuous beam is compared with measured maximum deflection of 9 span beam and found to agree reasonably well. The deflection of continuous beam due to moving load with acceleration is strongly influenced in the resonance region.

Dynamics of the system consisting of the hollow cylinder and surrounding infinite elastic medium under action an oscillating moving ring load on the interior of the cylinder

  • Akbarov, Surkay D.;Mehdiyev, Mahir A.
    • Coupled systems mechanics
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    • v.7 no.5
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    • pp.525-554
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    • 2018
  • The paper deals with the study of the dynamics of the oscillating moving ring load acting in the interior of the hollow circular cylinder surrounded by an elastic medium. The axisymmetric loading case is considered and the study is made by employing the exact equations and relations of linear elastodynamics. The focus is on the influence of the oscillation of the moving load and the problem parameters such as the cylinder's thickness/radius ratio on the critical velocities. At the same time, the dependence between the interface stresses and load moving velocity under various frequencies of this load, as well as the frequency response of the mentioned stresses under various load velocity are investigated. In particular, it is established that oscillation of the moving load can cause the values of the critical velocity to decrease significantly and at the same time the oscillation of the moving load can lead to parametric resonance. It is also established that the critical velocity decreases with decreasing of the cylinder's thickness/radiusratio.

Structural damage and force identification under moving load

  • Zhu, Hongping;Mao, Ling;Weng, Shun;Xia, Yong
    • Structural Engineering and Mechanics
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    • v.53 no.2
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    • pp.261-276
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    • 2015
  • Structural damage and moving load identification are the two aspects of structural system identification. However, they universally coexist in the damaged structures subject to unknown moving load. This paper proposed a dynamic response sensitivity-based model updating method to simultaneously identify the structural damage and moving force. The moving force which is equivalent as the nodal force of the structure can be expressed as a series of orthogonal polynomial. Based on the system Markov parameters by the state space method, the dynamic response and the dynamic response derivatives with respect to the force parameters and elemental variations are analytically derived. Afterwards, the damage and force parameters are obtained by minimizing the difference between measured and analytical response in the sensitivity-based updating procedure. A numerical example for a simply supported beam under the moving load is employed to verify the accuracy of the proposed method.

Dynamic response of a Timoshenko beam to a continuous distributed moving load

  • Szylko-Bigus, Olga;Sniady, Pawel
    • Structural Engineering and Mechanics
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    • v.54 no.4
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    • pp.771-792
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    • 2015
  • In the paper we study dynamic response of a finite, simply supported Timoshenko beam subject to a moving continuously distributed forces. Three problems have been considered. The dynamic response of the Timoshenko beam under a uniform distributed load moving with a constant velocity v has been considered as the first problem. Obtained solutions allow to find the response of the beam under the interval of the finite length a uniformly distributed moving load. Part of the solutions are presented in a closed form instead of an infinite series. As the second problem the steady-state vibrations of the beam under uniformly distributed mass $m_1$ moving with the constant velocity has been considered. The vibrations of the beam caused by the interval of the finite length randomly distributed load moving with constant velocity is considered as the last problem. It is assumed that load process is space-time stationary stochastic process.

Moving load induced dynamic response of functionally graded-carbon nanotubes-reinforced pipes conveying fluid subjected to thermal load

  • Tahami, F. Vakili;Biglari, H.;Raminnea, M.
    • Structural Engineering and Mechanics
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    • v.64 no.4
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    • pp.515-526
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    • 2017
  • Dynamic response of functionally graded Carbon nanotubes (FG-CNT) reinforced pipes conveying viscous fluid under accelerated moving load is presented. The mixture rule is used for obtaining the material properties of nano-composite pipe. The radial force induced by viscous fluid is calculated by Navier-Stokes equation. The material properties of pipe are considered temperature-dependent. The structure is simulated by Reddy higher-order shear deformation shell theory and the corresponding motion equations are derived by Hamilton's principal. Differential quadrature (DQ) method and the Integral Quadrature (IQ) are applied for analogizing the motion equations and then the Newmark time integration scheme is used for obtaining the dynamic response of structure. The effects of different parameters such as boundary conditions, geometrical parameters, velocity and acceleration of moving load, CNT volume percent and distribution type are shown on the dynamic response of pipe. Results indicate that increasing CNTs leads to decrease in transient deflection of structure. In accelerated motion of the moving load, the maximum displacement is occurred later with respect to decelerated motion of moving load.

Three-dimensional dynamics of the moving load acting on the interior of the hollow cylinder surrounded by the elastic medium

  • Akbarov, S.D.;Mehdiyev, M.A.;Ozisik, M.
    • Structural Engineering and Mechanics
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    • v.67 no.2
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    • pp.185-206
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    • 2018
  • This paper studies the non-axisymmetric 3D problem on the dynamics of the moving load acting in the interior of the hollow cylinder surrounded with elastic medium and this study is made by utilizing the exact equations of elastodynamics. It is assumed that in the interior of the cylinder the point located with respect to the cylinder axis moving forces act and the distribution of these forces is non-axisymmetric and is located within a certain central angle. The solution to the problem is based on employing the moving coordinate method, on the Fourier transform with respect to the spatial coordinate indicated by the distance of the point on the cylinder axis from the point at which the moving load acts, and on the Fourier series presentation of the Fourier transforms of the sought values. Numerical results on the critical moving velocity and on the distribution of the interface normal and shear stresses are presented and discussed. In particular, it is established that the non-axisymmetricity of the moving load can decrease significantly the values of the critical velocity.

Dynamic Analysis of the Beam Subjected to the Axial Load and Moving Mass (이동질량 및 축 하중의 영향을 받는 보의 동적 거동)

  • Lee, Kyu-Ho;Chung, Jin-Tai
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.21 no.3
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    • pp.271-279
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    • 2011
  • In this study, the dynamic analysis of a beam is analyzed by using the finite element method when the beam has moving mass and axial load. To consider the contact force between the moving mass and beam, coupled nonlinear equations of contact dynamics are derived, and then the weak form for the finite element method is established. The finite element computer programs based on the Lagrange multiplier method are developed to compute the contact force. Furthermore, a variety of simulations are performed for various design parameters such as moving mass velocity, compressive axial load and tension load. Finally, relations between the dynamic response and contact force are also discussed.