Anti-yaw Dampers Research Articles

Failure time prediction for vehicle dynamics under performance degradation of dampers and track evolution

During long-term service, railway vehicles will experience damper performance degradation and track evolution, both have significant effects on the vehicle dynamics performance. This study aims to develop a mathematical model for assessing the failure time of the vehicle system dynamics when considering two random factors. As for the methodology, Wiener processes are used to propose a damper degradation model. Moreover, a continuous-time Markov chain is adopted to describe the state transaction of the track irregularities. In addition, the Monte Carlo method is employed to sample the dynamic responses of the vehicle using stochastic parameters. Finally, the Bayesian theory is utilized to establish the reliability model of the Weibull mixtures under the Dirichlet process prior. The results are obtained through a numerical example: the dampers’ individual differences directly affect effect on the rate of degradation of the vehicle dynamics performance. Furthermore, different indexes positively correlate with each other, mixture models are composed of a small number of components, and Weibull mixtures closely approximate the distribution of the failure time. Compared to other dampers, the anti-yaw dampers have a more significant impact on the vehicle system dynamics. Other results show that each type of damper can adopt a uniform replacement period whereas anti-yaw dampers should be more effectively monitored.

Research on the Characteristics of Wheel Hollow Wear and Suppression Measures of High-Speed Trains

Wheel hollow wear is a serious problem of high-speed electric multiple units (HSE). The wheel wear characteristics of the CRH5 HSE are investigated using test data and simulation results. Then an HSE dynamics model and wheel wear model are established. Two assessment indicators for wheel hollow wear are proposed: the wheel wear simplification index and the contact fatigue index. Finally, some suppression measures of wheel hollow wear are proposed. The wheel wear simplification index is calculated simply and with strong engineering applicability. The fatigue index can effectively assess the fatigue level of different hollow wear. For the vehicle with the larger wheel profile hardness, the larger equivalent damping, and the smaller node stiffness of the anti-yaw damper, rail profile grinding can effectively suppress the wheel hollow wear of HSE. The research provides ideas for the design of bogies for HSE.

Stepwise Adaptive Convolutional Network for Fault Diagnosis of High-Speed Train Bogie Under Variant Running Speeds

Fault diagnosis of high-speed train (HST) bogie plays an indispensable role in guaranteeing the safety and stability of the daily operation of HST. Up to now, the well-established fault diagnosis models of HST bogie, which are usually trained by supervised learning mechanism, require that the training and testing data satisfy the same probability distribution. Consequently, those methods could lose their efficacy when the probability distribution of the testing data is changed owing to the variation of HST running speed and the labeled data corresponding to the changed speed is absent. To address this, a stepwise adaptive convolutional network (SACN) is proposed to learn the domain-invariant features of vibration data in different speed domains. Moreover, a novel in-and-out stepwise transfer method is designed to deal with the scenario of continuous change in vehicle speed. The experimental tests of the proposed method are conducted using the dataset acquired by SIMPACK via the HST model CRH380 A, mainly addressing the single and compound failure classification problem of the three key components of HST bogie, namely, the air spring, antiyaw damper, and lateral damper. Overall, the proposed SACN achieves an average accuracy of 96.1%, demonstrating the remarkable performance of domain adaptation in performing fault diagnosis of HST bogie under variant running speeds.

Suspension Parameters Optimization of Fast Freight Wagon Based on Low Wheel-Rail Dynamic Interactions

The dynamic model of fast freight wagon is established to study the effect of key parameters of the freight wagon on dynamic performance. In order to reduce the wheel-rail dynamic interactions, the parameters such as primary suspension stiffness, arm joint stiffness, and joint stiffness of the anti-yaw damper are optimized. The results indicate that the above suspension parameters have an influence on the fast freight wagon’s dynamic performance. Compared with the simulation results of the original parameters, the wheel-rail vertical force is reduced by 10%, and the wheel-rail lateral force is reduced by 42% and 38% respectively under the straight and curve conditions of the empty vehicle. The wheel-rail vertical force is reduced by 10% and 6%, and the wheel-rail lateral force is reduced by 10% and 16% respectively under the straight and curve conditions of the loaded fast freight wagon. The running stability and safety of the fast freight wagon have been improved.

<b>Development of Active Bogie Steering System to Improve Curving Performance</b>

This paper presents an active steering system designed to ensure both the curving performance and running stability of a vehicle. Electro-hydraulic actuators installed in place of anti-yaw dampers generate a yaw moment between the carbody and bogie. The system detects curves with gyroscopes mounted on the vehicle. This configuration enables the reduction of wheel/rail lateral force without requiring complicated mechanical links in the bogies. The actuators also work as anti-yaw dampers during high-speed running to ensure running stability.

Development method and experimental verification of fatigue load spectrum of anti-yaw damper for rail vehicles

The fatigue failure of anti-yaw damper seats on the carbody of railway vehicles is found during operation. The load time histories were obtained through calibration tests and field tests, and a novel load spectrum development method was proposed based on the field test results.The results show that the anti-yaw damper load presents the quasi-static characteristic within the frequency range of 5 Hz. The largest load impact on the anti-yaw damper seat appears when the vehicles pass through turnouts. Fatigue tests of the original and improved structures were carried out based on the proposed load spectrum. The fatigue failure phenomena of the damper seat were reproduced in the bench test. It is verified that the fatigue strength of the anti-yaw damper seat with improved structure meets the application requirements. This novel load spectrum development method could provide a reference for the design of other vehicle structures.

Suppression of abnormal chattering of a high-speed EMU carbody

A carbody chattering phenomenon accompanied by bogie hunting movement was investigated. The online test results showed that the vehicle at a large tread conicity state exhibited insufficient stability when running at higher speeds, causing the hunting frequency of the bogie to continuously increase and approach the diamond-shaped deformation modal frequency of the carbody, consequently causing the carbody to chatter. To improve the running stability of the vehicle and to suppress the carbody chattering, a two-step progressive optimisation method that combined analytical optimisation and simulation optimisation to optimise the parameters of the anti-yaw damper was proposed. Furthermore, the effect of optimisation was experimentally verified. Results showed that after optimisation, the critical speed of the vehicle under the condition of worn wheel was significantly enlarged, the bogie exhibited no obvious hunting motion, carbody chatter was significantly alleviated, and both the ride quality and the curve passing performance were improved.

Effect of the Anti-Yaw Damper on Carbody Vertical Vibration and Ride Comfort of Railway Vehicle

The theoretical research on means to reduce the vertical vibrations and improve the ride comfort of the railway vehicle relies on a mechanical model obtained from the simplified representation of the vehicle, while considering the important factors and elements affecting the vibration behaviour of the carbody. One of these elements is the anti-yaw damper, mounted longitudinally, between the bogie and the vehicle carbody. The anti-yaw damper reduces the lateral vibrations and inhibits the yaw motion of the vehicle, a reason for which this element is not usually introduced in the vehicle model when studying the vertical vibrations. Nevertheless, due to the position of the clamping points of the anti-yaw damper onto the carbody and the bogie, the damping force is generated not only in the yawing direction but also in the vertical and longitudinal directions. These forces act upon the vehicle carbody, impacting its vertical vibration behaviour. The paper analyzes the effect of the anti-winding damper on the vertical vibrations of the railway vehicle carbody and the ride comfort, based on the results derived from the numerical simulations. They highlight the influence of the damping, stiffness and the damper mounting angle on the power spectral density of the carbody vertical acceleration and the ride comfort index.

Test technology research and fatigue damage prediction of a car body based on dynamic simulation load spectrum

The dynamic model of a high-speed electric multiple unit (EMU) is established based on the theory of rigid-flexible coupling multi-body system dynamics. Depending on the actual operating conditions of the vehicle, there are a variety of conditions of car body load-time history. We assess ineffective amplitude omission, load spectrum extrapolation, and extreme determination through the car body load-time history, and then obtain the car body fatigue load block spectrum. Finally, we perform a fatigue strength test on the whole car body on a car body fatigue test bench. It is shown that the accelerations of the three directions of the vehicle car body increase with increasing speed. When the train passes a curve, the lateral acceleration average becomes greater. There is also an increase in the car body accelerations in three directions when the train goes through a turnout or twisted line. Under the condition of a failed spring, the vertical acceleration of the car body is obviously increased. Anti-yaw damper failure will cause a significant increase in vehicle lateral acceleration. The failure of lateral and vertical dampers on the second suspension causes an insignificant acceleration increase in three directions. The car body acceleration increases the wear-type profile relative to the original profile in various working and speed level conditions a little. The influence on the damage of vehicle car body under various working conditions is predicted according to the obtained load spectrum.

Stochastic failure process of railway vehicle dampers and the effects on suspension and vehicle dynamics

Railway vehicle dampers undergo degradation and failure after long-term service. Bench tests in this paper indicate a stochastic failure process, in which damping characteristics follow bimodal random distributions between normal and failure; failure probability increases in the ageing process until it becomes deterministic. This failure mode may be neglected due to the probabilistic absence of failure, which poses great risk to reliability. Then, nonlinear suspension dynamics with stochastic failure is modelled; Itô stochastic differential rule and cumulant-neglect closure are adopted to derive moment equations. The scheme of progressive iteration is proposed to obtain fast-convergent and stable solutions for analysing the effect of stochastic failure process on vibration response. Further, numerical simulation of a vehicle with stochastic failure is performed for failure effects analysis on dynamical performance. The results demonstrate that the deterioration of failure probability and damping reduction amplitude leads to larger vibrations. The stochastic failure of secondary lateral damper and anti-yaw damper is harmful for lateral vehicle dynamics, while that of secondary vertical damper has negative effects on vertical ride quality. It is of great importance to pay full attention to the stochastic failure process of dampers for reliability and security of railway vehicles.

Analysis of the service life of railway hydraulic dampers considering temperature and loading

Hydraulic dampers are mainly used to maintain high-speed trains in a stable state when running at high speed. In this paper, an equivalent method for the lifetime of dampers is proposed to establish the relationship between the long-term loading test and the mileage in service condition. The performance degradation of the damper at different temperatures is calculated using the long-term loading test carried out under the corresponding temperature conditions. Arrhenius model is applied to convert the degradation under different temperatures, and the sensitive parameter is selected for the conversion of the damper’s performance degradation under different temperatures. An energy method is proposed to solve the problem of the damper lifetime under different loads, so as to achieve the equivalent of the damper between the long-term load test and the mileage in service condition. Finally, taking the anti-yaw damper of a certain type of high-speed train in China as the research object, the lifetime equivalent method proposed in this paper is applied and the result showed that the anti-yaw damper had remaining service life after 2.4 million kilometers of service.

Theoretical study on the effect of the anti-yaw damper for rail vehicles

Simplification of a complex model is an analytical method commonly adopted in engineering design and academic research. A simplified theoretical analysis model can help project planners or researchers to develop an integrative view of the effect of each component on the system performances, which allows them to understand the related engineering phenomena and make proper engineering judgments. Based on the widely used Maxwell constitutive model for anti-yaw dampers, a simple 4 degree-of-freedom model is established to derive a set of analytical formulas, including those for critical speed, anti-yaw damper force transfer function, and rational resistance factor, which control the stability, ride quality, and curving performance of rail vehicles, respectively. Based on the proposed analytical formulas, the impact of damper parameters and mounting positions of the anti-yaw damper on the stability, ride quality and curving performance are analyzed. Finally, trade-offs among stability, ride quality, and curving performance are also discussed.

Dynamic reliability evaluation of vehicle–track coupled systems considering the randomness of suspension and wheel–rail parameters

The ride quality and running safety of high-speed trains are directly influenced by uncertainties of some key parameters, such as the damping and stiffness coefficients of suspension systems, wheel–rail coefficient of friction and wheel–rail profiles. Dynamic reliability problems of vehicle–track coupled systems under the influence of the above random parameters are studied in this article. An efficient numerical method is presented by combining a prediction-based iterative solution technique with subset simulation method. The solution efficiency of deterministic responses is improved by means of efficient prediction of wheel–rail forces, and the number of deterministic solutions required is reduced by expressing a small failure probability as a product of large conditional probabilities. The accuracy and the efficiency of the present method are verified by comparing with the direct Monte Carlo simulation. The failure probability distribution curves of the lateral ride index on straight track and the derailment coefficient during curve negotiation are obtained and the reliability sensitivity analyses are also carried out. The main conclusions are given as follows: the reliability of the system is higher when the randomness of the parameters with greater sensitivity is not considered; the increase of the damping of anti-yaw damper or the wheel–rail coefficient of friction will improve the ride quality on straight track, but will lower the running safety when negotiating a curved track.

On the nonlinear dynamics of a high-speed railway vehicle with nonsmooth elements

• A comprehensive lateral mathematical model of a high-speed railway vehicle with nonsmooth elements is built. • Numerical methods are presented to investigate the nonlinear dynamics of high-speed railway vehicles. • Nonlinear dynamics of a Chinese high-speed railway vehicle is investigated. • Influences of primary system parameters on the nonlinear dynamics of a Chinese high-speed railway vehicle are illustrated. A comprehensive lateral mathematical model of a high-speed railway vehicle with 17 degrees of freedom is built to study its nonlinear dynamics on a straight line. The hunting stability is explored by using eigenvalue analysis , bifurcation diagrams and the first Lyapunov coefficient. Due to the non-smoothness in the wheel/rail contact table and the secondary suspension elements such as anti-yaw dampers, bump stops , etc., an event-driven strategy is applied in the integration process of the ODEs . As an example, the nonlinear dynamics of a Chinese Railway High-speed (CRH) vehicle (named CRH2) is investigated. The result shows that the stable equilibrium of the high-speed railway vehicle loses its stability through a supercritical Hopf bifurcation with the increase of the forward speed, and the stable periodic solution loses its stability through a grazing bifurcation with the decrease of the forward speed. The influence of primary system parameters on the hunting stability of the high-speed railway vehicle is also investigated.

Fault Diagnosis of High-speed Train Bogie Based on Deep Neural Network

As an important part of high-speed train (HST), the performance of bogie has a direct impact on the safety of train. Real-time monitoring and evaluation of the operating state of bogie are of great significance for the safe operation of the train. The traditional signal processing methods are difficult to analyze the complex vibration signals of bogie which are collected during train operation. Deep Neural Network (DNN) has been widely used in the field of fault diagnosis due to its good performance in feature extraction of complex data. In this paper, DNN is taken as the overall framework. Failure modes include four states: air springs completely fail, anti-yaw dampers completely fail, lateral dampers completely fail and normal operation. In these four states, HST is running at the speed of 200km/h. Using the data collected in one hour of simulation as the input signal of DNN, the diagnostic accuracy of the four working conditions reached 92.5%. Experimental result shows that DNN has a good performance in multi-class fault diagnosis of bogie.

Estimation of dynamic performances of the safe operation of high-speed electric train

The process of implementation of new developments, in particular, new generation rolling stock holds a prominent place among the range of measures for organization of high-speed passenger rail transportation in Ukraine. The example of permission for use and the initial phase of work with interregional NRCS2 dual-mode electric trains produced by Hyundai-Rotem Corporation is the illustrative one in this context. Due to the detection of macro-cracks in bolster beams of the car body frames of these electric trains, namely in the areas of mounting of anti-yaw dampers, these trains were taken out of service until the completion of the modernization of problematic nodes. The comprehensive study on the determination of the safety parameters of electric trains was conducted to determine the causes of destruction of bolster beams. At the same time, bolster beams loading was estimated depending on the characteristics of anti-yaw dampers by means of computer simulation of the dynamics of motion of trailing and motor cars. The feasibility of selection of parameters for anti-yaw dampers mounted on electric train cars was assessed. The results of work will improve the safe operation of high-speed trains and increase the efficiency of estimates regarding the loading of bearing structures of underframes of the of rolling stock.

3D Suspension Characterization of a Rapid Transit Vehicle Using a Multi-Body Dynamic Model

In this work, suspension characterization of a rapid transit vehicle is performed with a multi-body dynamic model that represents full degrees of freedom of a rapid transit vehicle. The effects of lateral suspension properties on passenger ride comfort and stability are investigated by variation of critical suspension parameters using design of experiment method. The critical suspension properties are obtained for the best values of car body lateral acceleration and car body lateral stroke. The tangent track time response of the car body verified the negligible effect of both lateral viscous dampers at primary suspensions and longitudinal anti-yaw dampers at secondary suspensions on the passenger ride comfort and stability of a rapid transit vehicle.

A new parameter identification methodology for the bogie rotational resistance test of a rail vehicle

A more widespread use of the dynamic simulation of rail vehicles would become possible if the validation of the model was secured and the model parameters were known to be accurate. This paper proposes an analytical methodology for the objective identification of parameter values used in modelling rail vehicles, using the results of a bogie rotational resistance test defined in the acceptance process of railway vehicles (EN 14363). This methodology also takes into account the variability of the measuring process by providing a probabilistic estimation of the identified parameters. The methodology is experimentally validated using test results obtained for an Intercity vehicle. Seven model parameters can be accurately estimated: longitudinal and lateral stiffness of the air-spring secondary suspension, damping and force–speed characteristics of the anti-yaw dampers, longitudinal and lateral stiffness of the emergency spring, and lateral/longitudinal friction coefficient of the emergency spring; they all show excellent correlation with the component tests.

Fault detection and isolation for a nonlinear railway vehicle suspension with a Hybrid Extended Kalman filter

Fault detection is considered to be one way to improve system reliability and dependability for railway vehicles. The secondary lateral and anti-yaw dampers are the most critical parts in railway suspension systems. So far, the dampers have been modelled as linear components in the fault detection and isolation observer design. In this work, a Hybrid Extended Kalman filter is used to capture the nonlinear characteristics of the dampers. In order to detect and isolate faults, a nonlinear residual generator is developed, which can distinguish clearly between different types of faults. A lateral half train model serves as an example for the proposed technique. The results show that failures in the nonlinear suspension system can be detected and isolated accurately.

Control system with magnetorheological fluid device for mitigation of the railway vehicle hunting oscillations

The paper presents the opportunity of using a magnetorheological device to control the lateral oscillations of a passenger railway vehicle to increase its comfort and speed features. High speed generates large amplitude oscillations in horizontal plan at the axles, bogies and carbody levels which beyond a specific value – the critical speed – leads to unstable movement of the vehicle. The lateral dynamics of the vehicle is simulated using the multibody method. It is build a model with 17 degrees of freedom considering the lateral, yawing and rolling oscillations. An original device with magnetorheological fluid based on the balance logic strategy to control the anti-yaw damper is integrated in the secondary suspension of the railway vehicle. The conception and the design of the magnetorheological device are presented. It is demonstrated that the magnetorheological semi-active suspension improves the safety and the comfort of the railway vehicle.