High-Speed Vehicle Models Based on a New Concept of Vehicle/Structure Interaction Component: Part I—Formulation

1993 ◽  
Vol 115 (1) ◽  
pp. 140-147 ◽  
Author(s):  
L. Vu-Quoc ◽  
M. Olsson

High-speed vehicle/structure models constructed based on a new formulation of dynamic interaction between high-speed vehicles and flexible guideways are presented. A basic vehicle/structure interaction model forms a basic building block of complex vehicle/structure models in which lumped-parameter sub-components of the vehicle component (e.g., suspended masses with springs and dashpots) are assembled onto the basic vehicle/structure interaction component. A vertical and an inclined vehicle models are formulated. These vehicle models can serve as yet more advanced building-block models in the hierarchical construction of complex vehicle/structure models. The inclined vehicle model can be used to study the effects of braking of high-speed vehicles of flexible guideways. Fully nonlinear equations of motion of both models are given. Upon introducing approximations to the nonlinear kinematics, mildly nonlinear equations with an unusual mathematical structure are consistently derived. These equations are appropriate for use under realistic working conditions of the system, and are particularly amenable for numerical treatment using a recently proposed class of predictor/corrector algorithms.

1993 ◽  
Vol 115 (1) ◽  
pp. 148-155 ◽  
Author(s):  
L. Vu-Quoc ◽  
M. Olsson

The predictor structural equations for the vehicle models developed in Part I are derived here for use with a new class of predictor/corrector algorithms to solve the mildly nonlinear equations of motion of the vehicle/structure models. Having all accelerations of the vehicle component eliminated, and with the aid of further simplifying approximations, the predictor structural equations are linear with respect to the structural degrees of freedom. In the algorithms, the predictor structural equations are different from the corrector structural equations; the proposed algorithmic treatment has been proved (elsewhere) to yield accurate energy balance. Results obtained for both continuous and discontinuous guideways are discussed, and optimal guideway configurations suggested. Effects of high-speed vehicle braking on a flexible guideway are analyzed using the vehicle models and the proposed algorithmic treatment. The influence of the guideway flexibility on the vehicle speed, an important feature of the present formulation, is clearly demonstrated.


1989 ◽  
Vol 56 (2) ◽  
pp. 451-458 ◽  
Author(s):  
L. Vu-Quoc ◽  
M. Olsson

In traditional analyses of vehicle/structure interaction, especially when there are constraints between vehicle masses and the structure, vehicle nominal motion is prescribed a priori, and therefore unaffected by the structure flexibility. In this paper, a concept of nominal motion is defined, and a methodology is proposed in which the above restriction is removed, allowing the vehicle nominal motion to become unknown, and encompassing the traditional approach as a particular case. General nonlinear equations of motion of a building block model, applicable to both wheel-on-rail and magnetically levitated vehicles, are derived. These equations are simplified to a set of mildly nonlinear equations upon introducing additional assumptions — essentially on small structural deformation. An example is given to illustrate the present formulation.


2015 ◽  
Vol 31 (2) ◽  
pp. 217-225 ◽  
Author(s):  
J.-D. Yau ◽  
L. Frýba

ABSTRACTVehicle response is served as a reference to evaluate riding comfort of passengers and running safety of moving carriages for high speed trains. In analyzing the vehicle-bridge interaction (VBI) problems, two sets of coupled equations of motion for running vehicles and bridge need to be solved and the VBI system matrices must be updated and factorized at each time step in a time-history analysis. This paper proposed a quasi-VBI model to abridge the complicated computational process, in which the bridge is subjected to only moving static forces of the train loadings, and the moving vehicle over it is excited by the corresponding feedback bridge response. To examine the interacting degree of the vehicle with the bridge, a coupling evaluation index (CEI) is defined as a quantitative assessment of the VBI system. The numerical parametric studies reveal that (1) the mass ratio of vehicle to bridge is the most sensitive parameter affecting the bridge response; (2) increasing bridge damping can reduce the coupling degree of the VBI system at high speeds; (3) the present quasi-VBI model is an efficient and simple tool to predict the vehicle's response with enough accuracy based on engineering approximation.


2010 ◽  
Vol 26 (1) ◽  
pp. N9-N16
Author(s):  
C.-Y. Hu ◽  
K.-C. Chen ◽  
J.-S. Chen

AbstractThis study investigates the dynamic interactions between a vehicle and guideway of a high-speed ground transportation system based on maglev vehicles. The guideway is assumed to be made up of identical simply supported beams with single spans and rigid supports. The vehicle is considered to a two-dimensional vehicle model with primary and secondary suspensions. Three kinds of loading modes acting at each beam of guideway are first developed according to the locations of suspensions of vehicle. Coupled equations of motion of both vehicle and guideway in various loading modes are derived and solved by using numerical integration method. The simulations have been performed to investigate the parameters of vehicle/guideway system which may affect the steady-state responses of the vehicle and guideway.


Author(s):  
Michael A. Venturella ◽  
Mayuresh J. Patil ◽  
Leigh S. McCue

In this paper the authors present a multimode ice-structure interaction model based on the single degree of freedom ice-structure interaction model initially proposed by Matlock et al. (1969, “A Model for the Prediction of Ice-Structure Interaction,” Proceedings of the First Offshore Technology Conference, Houston, TX, Vol. 1, pp. 687–694, Paper No. OTC 1066; 1971, “Analytical Model for Ice Structure Interaction,” ASCE Journal of the Engineering Mechanics Division, EM4, pp. 1083–1092). The model created by Matlock et al. assumed that the primary response of the structure would be in its fundamental mode of vibration. In order to glean a greater physical understanding of the ice-structure interaction phenomena, it was critical that this study set out to develop a multimode forced response for the pier when a moving ice floe makes contact at a specific vertical pier location. Modal analysis is used in this study, in which the response of each mode is superposed to find the complete modal response of the entire length of a pier subject to incremental ice loading. This incremental ice loading includes ice fracture points as well as loss of contact between ice and structure. In the work of Matlock et al., the physical system is a bottom supported pier modeled as a cantilever beam. Realistic conditions such as ice accumulation on the pier modeled as a point mass and uncertainties in the ice characteristics are introduced in order to provide a stochastic response. The impact of number of modes in modeling is studied as well as dynamics due to fluctuations of ice impact height as a result of typical tidal fluctuations. A Poincaré based analysis following on the research of Karr et al. (1992, “Nonlinear Dynamic Response of a Simple Ice-Structure Interaction Model,” Proceedings of the 11th International Conference of Offshore Mechanics and Arctic Engineering, Vol. 4, pp. 231–237) is employed to identify any periodic behavior of the low and high velocity ice system responses. Recurrence plotting is also utilized to further define any existing structure of the ice-structure interaction time series for low and high speed ice floes. While the Matlock model on which this research is based is admittedly simplistic, the intention of this work is to provide a foundation for future work using time series analysis and modal analysis on more sophisticated models coupling multiple piers and connecting structure for a comprehensive ice-wind-structural dynamics model.


Nanoscale ◽  
2020 ◽  
Author(s):  
Fuping Zhang ◽  
Weikang Liu ◽  
Li Chen ◽  
Zhiqiang Guan ◽  
Hongxing Xu

he plasmonic waveguide is the fundamental building block for high speed, large data transmission capacity, low energy consumption optical communication and sensing. Controllable fabrication and simultaneously optimization of the propagation...


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