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Keywords: train dynamics, wheel rail contact, buffers contact, longitudinal forces, derailment, train simulator.

Summary

The paper is focused on the vehicle dynamics (mainly investigated in terms of wheel-rail force ratio and of the lateral force exchanged with the track) caused by the forces mutually exchanged, through buffers and draw gears, by consecutive vehicles. The results have been obtained by adding a buffers or draw gears contact model on an existing multibody code, previously developed by the authors. Moreover, the code developed considers a three-dimensional contact between the surfaces of the wheel and rail, by considering an elastic interaction between them.

The wheel-rail contact is simulated by means of an original contact model, called the third order approximation method (TOAM) capable of use as general user-defined wheel-rail profiles (for example acquired by means of experimental tests). The TOAM wheel-rail contact model has been developed to provide an accurate and computationally efficient method, able to detect a generic number of contemporaneous contact points, by simply looking for the minimum of a one-variable non-linear function. This model is based on an approximation on the wheel surface that allows a further analytical development of the mathematical problem. This model has been geometrically and dynamically verified by direct comparison with the output from commercial software [1,2].

The further development that has been introduced in this paper is the addition of a new module, which integrates the buffers contact in the multibody code; in this way, the multibody dynamics of three consecutive vehicles, subjected to longitudinal compressive forces (LCF), are investigated by computing the contact forces exchanged by the buffer heads of adjacent vehicles, running on a S shaped track. Not only the normal contact forces but also the friction forces between the buffer heads are considered in the proposed model, which supposes a planar geometric contact between the buffer heads and manages the real force-displacement characteristics of buffers and draw gears, as experimentally measured [3].

The numerical results have been verified here by means of direct comparison with experimental results given in [4]. The effect of some operational parameters, such as buffer gap and friction among buffer heads, are subsequently analyzed in the paper, justifying the common practice of employing a gap among buffer heads and by reducing the friction among themselves.

References

1: D. Negretti, "A third order approximation method for three-dimensional wheel rail contact", Vehicle System Dynamics, 2011. (accepted) doi:10.1080/00423114.2011.595804
2: L. Cantone, D. Negretti, V. Vullo, "Sviluppo e validazione di un modello semi-analitico del terz'ordine per l'analisi del contatto ruota rotaia", SEF 2011, Rome, Italy, 18 February, 2011.
3: L. Cantone, D. Negretti, "Modellazione dinamica disaccoppiata dei respingenti ferroviari", AIAS 2009 9-11 Settembre Torino, 2009.
4: ORE Question B 12, Report No. 40, "Propelling tests with long two-axle wagons", Utrecht, April 1984.

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Front Page Browse CCP CSETS CTR IJRT Other Authors Search Purchase Guide FAQ Contact us	Civil-Comp Proceedings ISSN 1759-3433 CCP: 96 PROCEEDINGS OF THE THIRTEENTH INTERNATIONAL CONFERENCE ON CIVIL, STRUCTURAL AND ENVIRONMENTAL ENGINEERING COMPUTING Edited by: B.H.V. Topping and Y. Tsompanakis Paper 25 The Train Dynamics of Wheel Rail Contact and Longitudinal Lateral Interaction between Vehicles L. Cantone, D. Negretti and V. Vullo Department of Mechanical Engineering, University of Rome "Tor Vergata", Italy doi:10.4203/ccp.96.25 purchase the full-text of this paper Full Bibliographic Reference for this paper L. Cantone, D. Negretti, V. Vullo, "The Train Dynamics of Wheel Rail Contact and Longitudinal Lateral Interaction between Vehicles", in B.H.V. Topping, Y. Tsompanakis, (Editors), "Proceedings of the Thirteenth International Conference on Civil, Structural and Environmental Engineering Computing", Civil-Comp Press, Stirlingshire, UK, Paper 25, 2011. doi:10.4203/ccp.96.25 Keywords: train dynamics, wheel rail contact, buffers contact, longitudinal forces, derailment, train simulator. Summary The paper is focused on the vehicle dynamics (mainly investigated in terms of wheel-rail force ratio and of the lateral force exchanged with the track) caused by the forces mutually exchanged, through buffers and draw gears, by consecutive vehicles. The results have been obtained by adding a buffers or draw gears contact model on an existing multibody code, previously developed by the authors. Moreover, the code developed considers a three-dimensional contact between the surfaces of the wheel and rail, by considering an elastic interaction between them. The wheel-rail contact is simulated by means of an original contact model, called the third order approximation method (TOAM) capable of use as general user-defined wheel-rail profiles (for example acquired by means of experimental tests). The TOAM wheel-rail contact model has been developed to provide an accurate and computationally efficient method, able to detect a generic number of contemporaneous contact points, by simply looking for the minimum of a one-variable non-linear function. This model is based on an approximation on the wheel surface that allows a further analytical development of the mathematical problem. This model has been geometrically and dynamically verified by direct comparison with the output from commercial software [1,2]. The further development that has been introduced in this paper is the addition of a new module, which integrates the buffers contact in the multibody code; in this way, the multibody dynamics of three consecutive vehicles, subjected to longitudinal compressive forces (LCF), are investigated by computing the contact forces exchanged by the buffer heads of adjacent vehicles, running on a S shaped track. Not only the normal contact forces but also the friction forces between the buffer heads are considered in the proposed model, which supposes a planar geometric contact between the buffer heads and manages the real force-displacement characteristics of buffers and draw gears, as experimentally measured [3]. The numerical results have been verified here by means of direct comparison with experimental results given in [4]. The effect of some operational parameters, such as buffer gap and friction among buffer heads, are subsequently analyzed in the paper, justifying the common practice of employing a gap among buffer heads and by reducing the friction among themselves. References 1 D. Negretti, "A third order approximation method for three-dimensional wheel rail contact", Vehicle System Dynamics, 2011. (accepted) doi:10.1080/00423114.2011.595804 2 L. Cantone, D. Negretti, V. Vullo, "Sviluppo e validazione di un modello semi-analitico del terz'ordine per l'analisi del contatto ruota rotaia", SEF 2011, Rome, Italy, 18 February, 2011. 3 L. Cantone, D. Negretti, "Modellazione dinamica disaccoppiata dei respingenti ferroviari", AIAS 2009 9-11 Settembre Torino, 2009. 4 ORE Question B 12, Report No. 40, "Propelling tests with long two-axle wagons", Utrecht, April 1984. purchase the full-text of this paper (price £20) go to the previous paper go to the next paper return to the table of contents return to the book description purchase this book (price £130 +P&P)
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