• Proceedings of the Computational Structural Engineering Institute Conference
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• 1996.04a
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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.

• 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.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2008.04a
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• pp.350-355
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• 2008

This paper addresses vibration comfort evaluation on suspension bridge subjected to moving vehicles. The moving load method is commonly employed for the analysis, even though it is less accurate than the moving mass approach which considers vehicle-bridge interaction effects and roughness of the pavement. In this study, a parametric study on modeling method by means of the moving load technique, such as the number of modes included in the analysis, types of moving loads, and length of the stiffening girder, is carried out. The numerical result indicated that use of the triangular pulse load may result in significant overestimation on vibration discomfortness.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1997.10a
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• pp.408-413
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• 1997

The linear dynamic response of a simply supported uniform beam under a moving load of constant magnitude is investigated. When the ratio of the moving weight and the structure weight is small, moving object is considered as a concentrated or distributed moving force, that is large external loading can be considered as a concentrated or distributed moving masses. Result from the numerical solutions of the differential equations of motion are shown graphically. Moreover, when considering the maximum deflection for the mid-span of the hewn, the critical speeds of the moving load have been evaluated.

• Geomechanics and Engineering
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• v.19 no.3
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• pp.241-254
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• 2019

A finite element approach is presented to examine ground vibration characteristics under various moving loads in a homogeneous half-space. Four loading modes including single load, double load, four-load, and twenty-load were simulated in a finite element analysis to observe their influence on ground vibrations. Four load moving speeds of 60, 80, 100, and 120 m/s were adopted to investigate the influence of train speed to the ground vibrations. The results demonstrated that the loading mode in a finite element analysis is reliable for train-induced vibration simulations. Additionally, a three-dimensional finite element model (3D FEM) was developed to investigate the dynamic responses of a track-ballast-embankment-ground system subjected to moving loads induced by high-speed trains. Results showed that vibration attenuations and breaks exist in the simulated wave fronts transiting through different medium materials. These tendencies are a result of the difference in the Rayleigh wave speeds of the medium materials relative to the speed of the moving train. The vibration waves induced by train loading were greatly influenced by the weakening effect of sloping surfaces on the ballast and embankment. Moreover, these tendencies were significant when the vibration waves are at medium and high frequency levels. The vibration waves reflected by the sloping surface were trapped and dissipated within the track-ballast-embankment-ground system. Thus, the vibration amplitude outside the embankment was significantly reduced.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1999.04a
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• pp.218-225
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• 1999

In order to completely automatize the moving load analysis for the three-dimensional frame model of the girder bridge, the efficient software technique is presented, which makes use of the signal among processes. If this software technique is used in automation, the separate algorithm is not needed for the transverse loading analysis, and the complete automatic moving load analysis algorithm can be easily developed. The program, which has the complete automatic moving load analysis function, has been developed with using this software technique, and has been verified by comparing the results with the one in the famous design book.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.23 no.11 s.170
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• pp.2058-2066
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• 1999

The present paper proposes a new dynamic analysis method for multi-span Timoshenko beam structures supported by joints with damping subject to moving loads. An exact dynamic element matrix method is adopted to model Timoshenko beam structures. A generalized modal analysis method is applied to derive response formulae for beam structures subject to moving loads. The proposed method offers an exact and closed form solution. Two numerical examples are provided for validating and illustrating the proposed method. In the first numerical example, a single span beam with multiple moving loads is considered. A dynamic analysis on a multi-span beam under a moving load is considered as the second example, in which the flexibility and damping of supporting joints are taken into account. The numerical study proves that the proposed method is useful for the vibration analysis of multi-span beam-hype structures by moving loads.

• Structural Engineering and Mechanics
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• v.52 no.1
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• pp.173-203
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• 2014

The cross-section warping due to the passage of high-speed trains can be a relevant issue to consider in the dynamic analysis of bridges due to (i) the usual layout of railway systems, resulting in eccentric moving loads; and (ii) the use of cross-sections prone to warping deformations. A thin-walled beam formulation for the dynamic analysis of bridges including the cross section warping is presented in this paper. Towards a numerical implementation of the beam formulation, a finite element with seven degrees of freedom is proposed. In order to easily consider the compatibility between elements, and since the coupling between flexural and torsional effects occurs in non-symmetric cross-sections due to dynamic effects, a single axis is considered for the element. The coupled flexural-torsional free vibration of thin-walled beams is analysed through the presented beam model, comparing the results with analytical solutions presented in the literature. The dynamic analysis due to an eccentric moving load, which results in a coupled flexural-torsional vibration, is considered in the literature by analytical solutions, being therefore of a limited applicability in practice engineering. In this paper, the dynamic response due to an eccentric moving load is obtained from the proposed finite element beam model that includes warping by a modal analysis.

• Advances in Computational Design
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• v.7 no.4
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• pp.371-393
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• 2022

This paper presents a three-dimensional flexible pavement simulated in ANSYS subjected to moving vehicular load on the surface of the pavement typical for the road section in Nepal. The adopted finite element (FE) model of pavement is validated with the classical theoretical formulations for half-space pavement. The validated model is further utilized to understand the damping and dynamic response of the pavement. Transient analysis of the developed FE model is done to understand the time varying response of the pavement under a moving vehicle. The material properties of pavement considered in the analysis is taken from typical road section used in Nepal. The response quantities of pavement with nonlinear viscoelastic asphalt layer are found significantly higher compared to the elastic pavement counterpart. The structural responses of the pavement decrease with increase in the vehicle speed due to less contact time between the tires of the vehicle and the road pavement.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1542-1549
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• 2011

The Transitional zone between bridge abutment and earthwork is one of the representative vulnerable zones in railway where differential settlements may take place due to the different supportive stiffness. Although transitional zones are managed with stricter standards than those of the other earthwork zones either in the design and construction stages, it is very difficult to prevent differential settlement perfectly. A three-dimensional numerical analyses were performed by applying train moving load in this study. The analytical model including abutments and earthwork zones was constituted with rail, sleepers, track concrete layer (TCL), hydraulic stabilized base (HSB), reinforced road bed, and road bed using railway and road base structure. The clamp connecting the rail and sleeper were also modeled as the element with spring coefficient. The train wheel is modeled in the actual size and moved on the rail with 300 km/hr speed. The deformation characteristics at each point of the rail and the ground were considered in detail when moving the train wheel. The analysis results were compared with those from the two-dimensional analysis without considering moving load. The research results show that displacement and stress were greater in the three-dimensional analysis than in other analyses, and the three-dimensional analysis with moving load should be performed to evaluate railway performance.