doi: 10.17586/2226-1494-2016-16-2-363-370

# MODELING OF RAIL BAR DYNAMIC GAP AT ITS BREAK FOR DIFFERENT STIFFNESS VALUES OF RAIL BASE

T. I. Zaitseva, A. M. Uzdin

Article in Russian

For citation: Zaitseva T.I., Uzdin A.M. Modeling of rail bar dynamic gap at its break for different stiffness values of rail base. Scientific and Technical Journal of Information Technologies, Mechanics and Optics, 2016, vol. 16, no. 2, pp. 362–370. doi:10.17586/2226-1494-2016-16-2-363-370

Abstract

Subject of Research.The paper deals with questions of operation safety for continuous welded rail track under dynamic loads. We study the gap value formed in the rail bar in view of its possible break under the conditions of dynamic loads caused by the moving train and varying temperatures. Occurring strains are linked to a variable stiffness of the rail track base (ballast). Methods. We studied longitudinal oscillations in a semi-infinite rod under dynamic loads and in the process of thermal expansion of the finite length rod on the elastic-damped foundation. Oscillatory processes in a semi-infinite rod on an elastic foundation was modeled using the extended equation of longitudinal vibrations, taking into account the reaction of the foundation, performing the role of a damper. To determine the state of the model after the damping of oscillations we used the time limiting transition. In solving the problem of thermal expansion of the finite length rod on the elastic foundation we used equilibrium equation for small fragment, which takes into account the thermal load and the elastic force of both the rod and the foundation. Main Results. We have calculated the maximum value of the dynamic displacement of the rod end at different values of parameters. We have obtained the distributions of stresses and displacements along the rod length for different stiffness distribution in the elastic foundation. In the event of accidental break in the rail, the gap value after the damping of oscillations is set at the level of 5-7 cm. We have shown that the amplitude of these oscillations can reach 10-12 cm. The availability of limited stiffness change zones in the rail base causes no significant deformation of rail bars, but can lead to the growth of the gap in the rail bar break. Practical Relevance. The proposed model can be used in the calculation and design of continuous welded rail tracks.

Keywords: gap, break, stiffness, strained deformed state, rail bar, rail base stiffness

Acknowledgements. The research was supported by the grants for Saint Petersburg young scientists of PSP series No. 12118 (2012) and No. 13156 (2013).

References

1. Bochenkov M.S. Zazory pri izlome rel'sovoi pleti. Trudy TsNII MPS, 1962, no. 244, pp. 164–172.
2. O napryazhenno-deformirovannom sostoyanii rel'sov pri izmenenii temperatury [About stress-strain state of the rails with varying temperature]. Vestnik TsNII MPS, 1967, no. 5, pp. 25–28.
3. Pan'kin I.A. Temperaturnye peremeshcheniya i napryazheniya v rel'sakh [Thermal displacements and stresses in the rails]. Trudy NIITa, 1972, no. 413, pp. 21–35.
4. Andreev G.G. Temperaturnye napryazheniya v besstykovom puti na mostakh [Thermal stresses in welded rails on the bridges]. Railway Track and Facilities, 1977, no. 12, pp. 34–35.
5. Vorob'ev E.V., Novakovich V.I. Osobennosti ustroistva i raboty besstykovogo puti [Features of the device and operation of welded rails]. Railway Track and Facilities, 2003, no. 4, pp. 15–19.
6. Kryukov E.P. Brus v uprugoi srede, soprotivlyayushchiisya prodol'nym smeshcheniyam [Brus in an elastic medium, resisting to longitudinal displacements]. Soobshchenie TsNIISa no. 137. Moscow, 1958, p. 86.
7. Anisimov V.M. Besstykovoi put' na mostakh [Welded road on the bridges]. Railway Track and Facilities, 1964, no. 8, p. 32.
8. Novakovich M.V. Zazor pri uchete vremeni ekspluatatsii [Gap at calculation of operating time]. Railway Track and Facilities, 2000, no. 11, p. 15.
9. Lalin V.V., Denisov G.V. The dynamic behavior of infinite rod elements on the visco-elastic foundation under point source of disturbance. Nauchnyi Vestnik Voronezhskogo GASU. Stroitel'stvo i Arkhitektura, 2013, no. 2, pp. 105–113.
10. Novakovich V.I., Grigor'eva I.A. Rel'sy dlya besstykovogo puti [Rails for welded way]. Railway Track and Facilities, 2001, no. 9, pp. 28–32.
11. Takagi R. High-speed railways. The last 10 years. Japan Railways & Transport Review, 2005, no. 3, pp. 4–7.
12. Peregudova M.V., Vinogorov N.P. Besstykovoi put' na mostakh [Welded road on the bridges]. Railway Track and Facilities, 2009, no. 3, pp. 26–28.
13. Beshliu A. Estimating the allowable gap size under rail trackway rupture from the point of view of train traffic safety. Prirodnye i Tekhnogennye Riski. Bezopasnost' Sooruzhenii, 2012, no. 3, pp. 56–57.
14. Zhanga G.-D., Guo B.-Z.. On the spectrum of Euler-Bernoulli beam equation with Kelvin – Voigt damping. Journal of Mathematical Analysis and Applications, 2011, vol. 374, no. 1, pp. 210–229. doi: 10.1016/j.jmaa.2010.08.070
15. Zaitseva N.I., Uzdin A.M. The effect of the railway bed stiffness change on the rail trackway deflected mode. Prirodnye i Tekhnogennye Riski. Bezopasnost' Sooruzhenii, 2012, no. 3, pp. 53–55.