Analysis of the dynamic response in the railway vehicles to the track vertical irregularities. Part II: The numerical analysis

Dumitriu, Mădălina

doi:10.25103/jestr.084.05

Cited by 29 publications

(16 citation statements)

References 6 publications

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“…For instance, a rise in the velocity from 50 to 140 km/h results into a 6-fold value for the RMS acceleration above axle 1 and 10-fold for the same acceleration above axle 2. Similarly, the bogie response is visibly not symmetrical above the two axles, due to the suspension damping and the geometric filtering effect from the bogie wheelbase [24]. The difference between the RMS accelerations in the bogie calculated above the two axles can reach almost 90%, as shown in Figure 5b.…”

Section: The Results Of the Numerical Simulationsmentioning

confidence: 95%

Fault detection of damper in railway vehicle suspension based on the cross-correlation analysis of bogie accelerations

Dumitriu

2019

Mechanics & Industry

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Nowadays, the condition-based maintenance is associated more and more with railway transport to improve the safety, availability, reliability and capacity of this transport system, and to reduce life cycle costs for the railway vehicles. The condition-based maintenance requires that vehicle components are replaced based on their real condition, which implies the fault detection and isolation during the train's operation. The paper proposes a method to detect the failure of the damper in the primary suspension of the rail vehicle, based on the analysis of cross-correlation of the vertical accelerations measured on the bogie frame against the two axles. The numerical simulations and experimental results show a very good correlation between the bogie accelerations when the dampers are in a normal operation condition. This thing is shown based on the values of the cross-correlation coefficient (CCC) of the bogie accelerations. The failure in a damper can be detected by the decrease of the CCC of the bogie accelerations, a confirmed fact in the results derived from numerical simulations. The proposed method has more advantages, namely, it is a signal-based method and hence does not require a complex mathematical modelling of the vehicle-track system and knowledge of its parameters or of the external conditions; the method makes relative comparisons between measurements and hence reduces the effect of the factors that influence outputs; the method can be also extended for the secondary suspension; the method can be easily implemented on any type of bogie.

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Section: The Results Of the Numerical Simulationsmentioning

confidence: 95%

Fault detection of damper in railway vehicle suspension based on the cross-correlation analysis of bogie accelerations

Dumitriu

2019

Mechanics & Industry

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“…What can be noticed in the diagrams are the peaks for the four resonance frequency of bending and the ones corresponding to the vibration rigid modes-the resonance frequency of the carbody bounce and the resonance frequency of the carbody pitch. Apart from these resonance peaks, a series of anti-resonance frequencies can be identified due to the geometric filtering effect [21,[44][45][46][47]. Based on the diagrams in Figure 4, the influence of the vertical bending upon the level of vertical vibrations in the carbody reference points in correlation with velocity is analysed.…”

Section: Resultsmentioning

confidence: 99%

Influence of Bending Vibration on the Vertical Vibration Behaviour of Railway Vehicles Carbody

Dumitriu

Dihoru

2021

Applied Sciences

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The topic of reducing structural vibrations in the case of flexible carbodies of railway vehicles has been intensively studied, but it is still an active research topic thanks to the importance of the perspective of improving the ride comfort. However, no study has been identified in the specialty literature to feature the contribution of the vibration structural modes upon the vibration behaviour of the railway vehicle carbody. The structural vibration modes of the flexible carbodies are particularly complex; however, the first vertical bending mode holds great significance in terms of the ride comfort. This paper analyses the influence of the first vertical bending mode on the vibration behaviour in three reference points of the railway vehicle carbody in correlation with the carbody flexibility, the vehicle velocity and the suspension damping. This study relies on comparisons between the results of the numerical simulations obtained for a ‘flexible carbody’ type model of the vehicle and the ones obtained for a ‘rigid carbody’ type model. The first part of this study analyses the characteristics of the vertical vibrations behaviour of the flexible carbody based on the dynamic response of the vehicle and expressed as the acceleration power spectral density. In the second part, the influence of the vertical bending on the vertical vibrations level of the carbody is analysed using the root mean square of the vertical acceleration.

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“…Indeed, a first resonance is in the frequency range [50;30 Hz], a second one is in the frequency range [200;600 Hz], and a third one is located around 1000 Hz as explained in [31]. On the other hand, natural vibrations of the vehicle motion are in the area of [0;20 Hz] [30,32]. Therefore, the vertical track loading is due to:…”

Section: Track Loadingmentioning

confidence: 99%

An Efficient Numerical Model to Predict the Mechanical Response of a Railway Track in the Low-Frequency Range

et al. 2022

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With railway interoperability, new trains are allowed to move on the French railway network. These trains may present different designs from standard trains. This work aims to complete the current approach for vehicle admission on the railway network, which is defined in technical baselines. Historically, computation rules for traffic conditions are based on simplified analytical works, which are considerably qualitative. They have evolved through feedback and experimental campaigns to comply with the track structure evolution. An efficient methodology based on numerical simulation is needed to evaluate railway vehicle admission to answer this issue. A perspective to update these computation rules is to evaluate the structural fatigue in the rail. That is to say, fatigue is caused by bending and shear stresses. The complexity of the railway system has led to an investigation at first of the vertical response of the railway track and quantifying its contribution to the rail’s stress response. In that sense, this paper investigates the vertical track response to a moving railway vehicle at low frequencies. For this purpose, a lightweight numerical model for the track, a multi-body model for the vehicle, and a random vertical track irregularity are proposed. More explicitly, the track model consists of a two-layer discrete support model in which the rail is considered as a beam and sleepers are point masses. The rail pads and ballast layer are modelled as spring/damper couples. Numerical results show a negligible effect of track inertia forces due to high track stiffness and damping. Nevertheless, this assumption is valid for normal rail stresses but not for ballast loading, especially in the case of sleeper voids or unsupported sleepers. Hence, the prediction of the mechanical stress state in the rail for fatigue issues is achieved through a static track model where the equivalent loading is obtained from a dynamic study of a simplified vehicle model. A statistical analysis shows that the variability of the vertical track irregularity does not influence the output variabilities like the maximum in time and space of the normal and shear stress.

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Analysis of the dynamic response in the railway vehicles to the track vertical irregularities. Part II: The numerical analysis

Cited by 29 publications

References 6 publications

Fault detection of damper in railway vehicle suspension based on the cross-correlation analysis of bogie accelerations

Fault detection of damper in railway vehicle suspension based on the cross-correlation analysis of bogie accelerations

Influence of Bending Vibration on the Vertical Vibration Behaviour of Railway Vehicles Carbody

An Efficient Numerical Model to Predict the Mechanical Response of a Railway Track in the Low-Frequency Range

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