Finite element model of wheel – Rail impact due to flat spot

Prasad, A. Bhavani; Jafferson, J.M.

doi:10.1016/j.matpr.2021.02.068

Cited by 4 publications

(2 citation statements)

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“…Baeza et al, 2008 applied the flexible wheelset model instead of the rigid wheel model and reported that the flexible wheelset model slightly reduces the simulated wheel-rail impact force. (Liu et al, 2022), A. Prasad and Jafferson, 2021and Zhao et al, 2014 finite element (FE) vehicle-track models to simulate wheel-rail impact at rail spalling, wheel flats, and squats, respectively. Compared to the multi-rigid-body model used in Wanming, 2007;Zhao et al, 2019, the 3D FE vehicletrack model is much more time-consuming despite the higher accuracy in simulating high-frequency wheel-rail dynamic interaction.…”

Section: Introductionmentioning

confidence: 99%

“…(Liu et al, 2022), A. Prasad and Jafferson, 2021 and Zhao et al, 2014 employed three-dimensional (3D) finite element (FE) vehicle-track models to simulate wheel-rail impact at rail spalling, wheel flats, and squats, respectively. Compared to the multi-rigid-body model used in Wanming, 2007; Zhao et al, 2019, the 3D FE vehicle-track model is much more time-consuming despite the higher accuracy in simulating high-frequency wheel-rail dynamic interaction.…”

Section: Introductionmentioning

confidence: 99%

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Characterization and mitigation of wheel-rail impact at a singular rail defect

Tao¹,

Zhang

2022

Journal of Vibration and Control

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Wheel-rail impact, which arises from structural discontinuities and short-wave defects, becomes more serious with higher train speeds and larger axle loads. The large impact load can accelerate the deterioration of vehicle-track components and induce a high level of impact noise. This paper aims to better understand the characteristics of wheel-rail impact and redevelop corresponding mitigation measures. First, a well-validated vehicle-track vertical interaction model with a singular rail defect is built up considering nonlinear Hertz contact. Then, the simulated wheel-rail impact force is characterized in both the time and frequency domains with different running speeds and defect geometries employing continuous wavelet transform. The identified characteristic frequencies are correlated to the track resonance modes. Afterward, a parameter sensitivity analysis of railpads, ballast, roadbed, and suspensions is performed to obtain the mitigation measures of wheel-rail impact. The results show that the wheel-rail impact force can be characterized by four stages in the time domain, the quasi-static stage before the impact, the forced vibration, the free vibration, and the quasi-static stage after the impact, respectively. Four characteristic frequencies are identified in the wheel-rail impact response: f1 at 45 Hz, f2 at 100 Hz, f3 at 260 Hz, and f4 at 810 Hz. Among them, f4 has the dominant vibration energy and is determined together by the pinned-pinned resonance mode and the defect excitation frequency. Characteristic frequencies f1, f2, and f3 correspond to the ballast, sleeper, and rail resonance modes, respectively, which are independent of the defect geometry. The increase of railpad stiffness can effectively reduce the maximum wheel-rail impact force and thus the impact factor. Larger railpad stiffness and damping can significantly reduce the dominant vibration energy at about 810 Hz of f4. This work can contribute to the optimization of vehicle-track parameters for a new design of more impact-resistant railways.

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