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Computer models of freight cars with three-piece and Y25 bogies are considered and compared. Efficient numeric methods for
simulation of vehicle models in the presence of frictional contacts are discussed. Some simulation results on derailment safety
analysis and influence of track gauge value on freight-car dynamics are presented. Methods of stres...
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Context 1
... value is exactly equal to the critical value 1 when the wheel "starts to climb." In case of a pair of profiles allowing the two-point contact, this position corresponds to the two-point contact with zero value of contact forces on the top of the rail (Fig. 5 left). In the case of profiles with one-point contact, the critical position corresponds to the flange contact in the point with the contact angle equal to the flange angle (Fig. 5 right). In both cases, further lift of the wheel leads to an increase in the contact angle which often results in the growth of the safety factor (4). Therefore, ...
Context 2
... case of a pair of profiles allowing the two-point contact, this position corresponds to the two-point contact with zero value of contact forces on the top of the rail (Fig. 5 left). In the case of profiles with one-point contact, the critical position corresponds to the flange contact in the point with the contact angle equal to the flange angle (Fig. 5 right). In both cases, further lift of the wheel leads to an increase in the contact angle which often results in the growth of the safety factor (4). Therefore, it cannot be used for assessment of wheel climb beyond the critical position shown in Fig. 5. Second, the relative vertical displacement of a wheel over the critical position is ...
Context 3
... to the flange contact in the point with the contact angle equal to the flange angle (Fig. 5 right). In both cases, further lift of the wheel leads to an increase in the contact angle which often results in the growth of the safety factor (4). Therefore, it cannot be used for assessment of wheel climb beyond the critical position shown in Fig. 5. Second, the relative vertical displacement of a wheel over the critical position is evaluated according to the formula where z is the lift of the wheel (Fig. 6). Like the refined safety factor S RU,r , the lifting factor S z is equal to unity at the critical position ( Fig. 5). Finally, the formula for the factor combination of S RU,r ...
Context 4
... for assessment of wheel climb beyond the critical position shown in Fig. 5. Second, the relative vertical displacement of a wheel over the critical position is evaluated according to the formula where z is the lift of the wheel (Fig. 6). Like the refined safety factor S RU,r , the lifting factor S z is equal to unity at the critical position ( Fig. 5). Finally, the formula for the factor combination of S RU,r and S z in (4) and (5) ...
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Abstract
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Citations
... The wedges are not modelled as separate bodies, but an equivalent force against displacement characteristics is introduced accounting for wedge parameters like inclination angle, vertical surface width, inclined surface width, and friction coefficients on inclined and vertical surfaces, as presented in Figure 5(c). The second approach to account for all possible degrees of freedom between side frame and bolster is to introduce multiple contact points mapped along the edges of the wedge with two-dimensional friction force elements in each of them [37]. ...
... The interaction of dry friction between the axle box crown and the side frame pedestal is represented by a twodimensional dry friction element in conjunction with a nonlinear element that characterises bump stops in both longitudinal and lateral dimensions. An alternative method involves incorporating several contact sites along the crown's edges, featuring twodimensional friction features [37]. The bump stops serve as the contact elements between the axle box or adapter and the stops within the side frame jaws. ...
... The initial approach [35,36] involves the interaction between the centre plate and centre bowl, functioning concurrently as one-dimensional yaw friction and nonlinear roll and pitch torque with pliable attributes. An alternative method [37] involves incorporating numerous contact sites along the periphery of the central plate, featuring two-dimensional friction elements within them. ...
Train-track coupled dynamics problems are particularly prominent in heavy-haul railways, due to the strong coupling effects of longitudinal , lateral, and vertical interactions between long heavy-haul trains and rail infrastructure. Poor train-track dynamic interaction performance could lead to a series of dynamics problems that significantly influence train operational safety and maintenance costs. This paper presents a comprehensive state-of-the-art review of train-track coupled dynamics theory and its applications in heavy-haul rail transportation. Several critical heavy-haul train-track coupled dynamics problems are discussed, including longitudinal coupler force induced safety issues, wheel-rail wear and rolling contact fatigue, and infrastructure degradation due to train-track interactions. The evolution of vehicle-track coupled dynamics theory and its extended development to heavy-haul train-track coupled dynamics is described briefly. A systematic review of the modelling methodology for key elements in heavy-haul train-track coupled dynamics is presented. Field test results focusing on the modelling validation are also briefly presented. The practical applications of heavy-haul train-track coupled dynamics theory are comprehensively discussed. Guidance is provided on further improving the heavy-haul train-track coupled dynamics and identifying future challenging research topics on better solving complicate engineering problems due to heavy-haul rail transportation.
... Consequently, the use of multibody dynamic simulation reduces the effort required for these type of studies, while results can be obtained with good reliability in a acceptable amount of time. Regarding the present topic, Roman Kovalev [2], performed a comparative between the Y-25 bogie and the 3-piece bogie using Universal Mechanism software. The model used for this comparison consisted of 15 rigid bogies, a full modelization of Lenoir damper and several contacts between rigid bodies. ...
The freight bogie type Y-25 is the most used running gear in European freight wagons since its standardisation in 1967. Nonetheless, apart from several studies mostly focused on the primary suspension to improve the running characteristics, its design has barely changed over time. Up to date, there is rather little information and analyses related to the secondary suspension, limited to some standardised dimensional characteristics of its components, known as side bearers. In order to enhance the knowledge of these elements and their influence on the wagon operation, an analysis of the effect of the side bearers preload on different parameters related to the dynamic response of the wagon, such as the axle lateral force, wheel load transfer or bogie yaw velocity, is presented in this article for a Y-25 bogie. To this aim, a multibody model of a freight wagon with two Y-25 bogies is developed using Adams® and verified against the current normative for European freight wagons. The verified model is later subjected to varying suspension preloads, and the dynamic-related parameters for different wagon carrying loads, speed and track layouts are analysed. The results obtained provide relevant information that contributes to increase the understanding of the secondary suspension elements in Y-25 bogies.
... Since the Nadal Criteria for Derailment interests itself with the ratio of the lateral force to the vertical force at the wheel and rail contact point, together with the L/V parameter, Equation 14 relates the friction coefficient f to the summation of the forces presented as L/V along the respective axis and the flange angle. ...
... Resolution of Equation 14 to yield an L/V term results in Equation 15, which is Nadal's criterion for derailment (3). The combined vectors L and V begin to generate a compressive force at the contact point that initiates a friction force that develops into its final value F. The final compressive force pressing onto the railhead is N. Since as the wheel rolls around its normal rolling contact area, denoted by the regional area R, the sideways wheel motion may occasionally force the wheel to contact the flange. ...
... At this extreme, where the wheel flange is in contact with the railhead corner, under extreme circumstances, damage on both the track and the rail is definite, the development rate of which depends mainly on the tonnage on the track and the track maintenance conditions. Figures 13 presents sketches of worn rail and wheel profiles along track curves under extreme contact stress conditions (14). Figure 13. ...
Between the wheels of the train and the rails, there exist variable and triaxial stresses that include the vertical stresses, longitudinal stresses, and lateral stresses generated by the vertical, longitudinal, and lateral forces exerted by the train wheels on the rails. In addition to these stresses, there are residual in-plane and longitudinal stresses within the rails generated during their production and longitudinal stresses generated by ambient temperatures on continuously welded rails. The simultaneous presence of many types of stresses on rails with varying magnitudes that can be quite high generates unusual mechanical demands from the rails as opposed to other types of structural elements of civil engineering, which require special cross-sectional designs and metallurgical constituency. The type and magnitude of stresses along a railway route vary with the locations along the route with higher stresses along the acceleration and deceleration zones within and near the stations, horizontal curves, slopes, stiffness transition zones and turnouts. This study provides analytical insight into the magnitudes of vertical, longitudinal, and lateral forces that can occur at the wheel and rail interface and the analytical means to estimate these forces. The study later elaborates on the stresses that these forces can generate on the railhead and highlights the need for high-strength rail steel along railway routes and special rail profiles along curves.
... As a result, it will improve the Human-computer interaction, thus contributing positively totraffic safety. [13] ...
In this digital world, the computer is getting more and more useful., Over the course of several decades, computer have been really powerful beyond our wildest dreams. Especially in the car industry, computers have been widely used, because using computer to model the cars can have lots of advantages. With the help of the computers, people can improve their working efficiency and personal safety. What’s more, cars can also be safer, cheaper and higher performance by using computer. At first, the software like CAD was only used to directly engage in drawing graphics and making structure design. However, the software which was applied today nearly engage in every part of the cars. Computer modeling have already be a tendency. In this paper I will summary the advantages of the computer modeling and show how to use computer to model the casrs. In the end, I will also write the future development of the computer modeling.
... Fae analysis can be performed with Solidworks software. (Kovalev et al., 2009). The development of freight wagons and fae analysis can be done on Solidworks software. ...
Bu çalışmada bir yük vagonu şasi geometrisinde planlama performans değerleri ele alınmıştır. Yük vagonu olarak konteyner taşınabilen tipte şasiler tercih edilmiştir. optimizasyon metodu olarak topoloji optimizasyonu kullanılmıştır. Sonlu elemanlar (FEA) analizi için malzeme olarak 1023 çelik malzeme tercih edilmiştir. Yük vagonları için gerekli güvenlik limitleri dahilinde çalışma sonucunda geleneksel yük vagonunu %14,51 hafifletilmiştir. Yük vagonu daha hafif olmasına rağmen yük dağılımında da düzenli sonuçlar elde edilmiştir böylece standart bir yük vagonunun imalat maliyetleri düşürülmüştür. Demiryolu işletmeciliğinde yasal yük sınırlamaları vagon ağırlığı ve yükün toplamına kadardır. Herhangi bir yük vagonun darasındaki ağırlık iyileştirmeleri daha fazla yük taşınabileceği anlamına gelmektedir. Bu çalışma ile geleneksel bir yük vagonu şasisinin yalnızca imalat maliyetleri değil işletme maliyetlerine olumlu etkisi olduğu gözlemlenmiştir.
... Hertzian solution and FASTSIM algorithm by Kalker as well as modified non-elliptic multipoint contact model are used. Some researchers used this train model for dynamic simulations [26][27][28][29][30]. After completing the simulation of the train's dynamic characteristics in the UM input section, the UM simulation section has been used to simulate the dynamic behaviour of the system. ...
The two factors of track irregularity and train speed affect the dynamic behavior of rail vehicles and can lead to an increase in dynamic forces, a decrease in ride comfort, and derailment in some cases. In this paper, the effect of train speed increase and different conditions of track irregularity on ride comfort and ride quality are investigated. For this purpose, first, two freight and passenger train models have been modeled in UM software, and then the effect of train speed increase and track irregularities (different US federal classes) have been studied with Sperling’s index. A freight train with the model of 18-100 and 3-piece bogie and a TGV high-speed train with 10 wagons were simulated. The results showed that in Sperling’s index, with the increase in the train speed and irregularity amplitude, the value of ride comfort and ride quality generally increased. For example, in the passenger train and irregularity classes 5 and 4, with the increase in train speed from 10 to 100 m/s, the Sperling’s index values changed from 0.66 to 1.99 and from 0.78 to 2.25, and increased 200% and 188%, respectively. In other words, at a speed of 10 m/s, passengers' comfort is just noticeable, while at a speed of 100 m/s and class 4, the situation is more pronounced but not unpleasant and the system should be monitored.
... Rezvani and Mazraeh [27] studied the effects of wheel/rail friction coefficient and track curve radius on the nonlinear critical speed. By comparing the models of three piece and Y25 bogie, Kovalev et al. [28] discussed a numerical method of simulating the vehicle model in the presence of friction contact and gave the derailment safety analysis. Stichel [29] studied the nonlinearity of the two-axle freight car, especially the influence of friction damping on the running behavior of the freight wagon and gave the bifurcation curve and the limit cycle diagrams. ...
Traditional vertical vibration models of rail vehicle usually have high degrees of freedom, which affects the efficiency of numerical simulation. Regardless of the coupling effect between the vehicle and rail, a six degree of freedom (6DOF) quarter model with vertical displacement and rotation angle is selected as the dynamic model. This accomplished by comparing the simulation results of half model and quarter model of the railway freight wagon, and the vertical vibration characteristics of the railway freight wagon when the wagon speed is changed. To further illustrate the nonlinear vibration characteristics and evolution laws of the car body and bogie frame of the freight wagon, the bifurcation diagrams, maximum Lyapunov exponent curves, axis trajectory curves, phase plane plots, Poincaré sections, and amplitude spectras are drawn and adopted to research the dynamic responses. The simulations reveal the complex vibration behavior such as periodic, quasi-periodic, multi-periodic, and chaotic motion. Some research results can help the industry to better design the speed limits of such railway freight wagons, and deeply understand or utilize the vertical vibration law of railway freight wagon in future research.
... Over the years, freight railway traffic has experienced progressive growth in transported goods, which consequently leads to an increase in the number of operating trains, speeds and axle loads. These changes are responsible for an increase in the dynamic loads induced by the freight vehicles on the railway infrastructure, potentially affecting the running safety, the stability of the transported goods and durability of the components of vehicle and infrastructure [1][2][3][4][5]. ...
The simulation of the dynamic behavior of the train-track system is strongly dependent on the accuracy of the numerical models of the train and track subsystems. The use of calibrated numerical models of the railway vehicles, based on experimental data, enhances their ability to correctly reproduce the dynamic responses of the train under operational conditions. In this scope, studies involving the experimental calibration of freight wagon models are still scarce. This article aims to fill this gap by presenting an efficient methodology for the calibration of a numerical model of a freight railway wagon based on experimental modal parameters. A dynamic test was performed during the unloading operation of the train, adopting a dedicated approach which does not interfere with its tight operational schedule. From data collected during the dynamic test, five natural frequencies and mode shapes associated with rigid-body and flexural movements of the wagon platform were identified through the Enhanced Frequency-Domain Decomposition (EFDD) method. A detailed 3D finite-element (FE) model of the loaded freight wagon was developed, requiring precise knowledge of the vehicle design details which, in most situations, are difficult to obtain due to confidentiality reasons of the manufacturers. The model calibration was performed through an iterative method based on a genetic algorithm and allowed to obtain optimal values for seven numerical parameters related to the suspension’s stiffnesses and mass distribution. The stability of the parameters considering different initial populations demonstrated the robustness of the optimization algorithm. The average error of the natural frequencies decreased from 8.5% before calibration to 3.2% after calibration, and the average MAC values improved from 0.911 to 0.950, revealing a significant improvement of the initial numerical model.
... In particular, the friction wedge used in the three-piece bogie and the Lenoir link used in the Y25 bogie are critical elements that require special attention for successful and accurate computer simulations. Developing such accurate computer models of rail vehicles is necessary because of their impact on improving the performance, efficiency, and operating cost [30]. Previous studies have shown that freight cars equipped with three-piece bogies have increased risk of derailment as compared to the Y25 bogie [30,38]. ...
... Developing such accurate computer models of rail vehicles is necessary because of their impact on improving the performance, efficiency, and operating cost [30]. Previous studies have shown that freight cars equipped with three-piece bogies have increased risk of derailment as compared to the Y25 bogie [30,38]. In this investigation, computer simulations results are used to obtain recorded motion trajectories that allow extracting specific performance measures. ...
... The Y25 bogies can also have a secondary suspension consisting of two sets of coil springs located between the frame and Frenet force analysis in performance evaluation of railroad vehicle systems the car body. While the admissible Y25 axle loads are not as high as allowed by three-piece bogies, previous studies reported lower risk of derailment during curve negotiations for the Y25 bogie [30]. ...
A data-driven science approach, based on integrating nonlinear multibody system (MBS) formulations and new geometric concepts, is used in this paper to compare the performance of two widely used railroad bogies: the three-piece bogie and the Y25 bogie. MBS algorithms are used to solve the bogie nonlinear differential/algebraic equations (DAEs) to determine the bogie motion trajectories. To have a better understanding of the bogie dynamic behavior, a distinction is made between the geometry of actual motion trajectories (AMT) and the track geometry. The AMT curves are described using the motion-dependent Frenet–Euler angles, referred to as Frenet bank, curvature, and vertical development angles, which differ from their counterparts used in the description of the track geometry. In particular, the Frenet bank angle defines the super-elevation of the AMT curve osculating plane, referred to as the motion plane, distinguishing this Frenet super-elevation from the fixed-in-time track super-elevation. The paper explains the difference between the lateral track plane force balance used in practice to determine the balance speed and the Frenet force balance which is based on recorded motion trajectories. Computer simulations of bogies travelling on a track, consisting of tangent, spiral, and curve sections are performed with particular attention given to the deviations of the AMT curves from the track centerline. The results obtained in this study demonstrate the dependence of the AMT curve geometry on the wheelset forward motion, highlighting the limitations of tests performed using roller test rigs which do not allow longitudinal wheelset motion.
... The lateral and vertical friction is modelled as dry Coulomb friction, where the friction force is proportional to the normal load. More description can be found in [63]. There is no real secondary suspension on the Y25 bogie. ...
The selection of a wheel profile is a topic of great interest as it can affect running performances and wheel wear, which needs to be determined based on the actual operational line. Most existing studies, however, aim to improve running performances or reduce contact forces/wear/rolling contact fatigue (RCF) on curves with ideal radii, with little attention to the track layout parameters, including curves, superelevation, gauge, and cant, etc. In contrast , with the expansion of urbanization, as well as some unique geographic or economic reasons, more and more railway vehicles shuttle on fixed lines. For these vehicles, the traditional wheel profile designing method may not be the optimal choice. In this sense, this paper presents a novel wheel profile designing method, which combines FaSrtip, wheel material loss function developed by University of Sheffield (USFD function), and Kriging surrogate model (KSM), to reduce wheel wear for these vehicles that primarily operate on fixed lines, for which an Sgnss wagon running on the German Blankenburg-Rübeland railway line is introduced as a case. Besides, regarding the influence of vehicle suspension characteristics on wheel wear, most of the studies have studied the lateral stiffness, longitudinal stiffness, and yaw damper characteristics of suspension systems, since these parameters have an obvious influence on wheel wear. However, there is currently little research on the relationship between the vertical suspension characteristics and wheel wear. Therefore, it is also investigated in this paper, and a suggestion for the arrangement of the vertical primary spring stiffness of the Y25 bogie is given.
