Model Of Bogie Research Articles

Integration of bio-inspired limb-like structure damping into motor suspension of high-speed trains to enhance bogie hunting stability

Hunting stability is an important performance criterion in railway vehicles. This study proposes an incorporation of a bio-inspired limb-like structure (LLS)-based nonlinear damping into the motor suspension system for traction units to improve the nonlinear critical speed and hunting stability of high-speed trains (HSTs). Initially, a vibration transmission analysis is conducted on a HST vehicle and a metro vehicle that suffered from hunting motion to explore the effect of different motor suspension systems from on-track tests. Subsequently, a simplified lateral dynamics model of an HST bogie is established to investigate the influence of the motor suspension on the bogie hunting behavior. The bifurcation analysis is applied to optimize the motor suspension parameters for high critical speed. Then, the nonlinear damping of the bio-inspired LLS, which has a positive correlation with the relative displacement, can further improve the modal damping of hunting motion and nonlinear critical speed compared with the linear motor suspension system. Furthermore, a comprehensive numerical model of a high-speed train, considering all nonlinearities, is established to investigate the influence of different types of motor suspension. The simulation results are well consistent with the theoretical analysis. The benefits of employing nonlinear damping of the bio-inspired LLS into the motor suspension of HSTs to enhance bogie hunting stability are thoroughly validated.

Dynamic vibration absorber for the mitigation of potential wheel polygonization at trams

Polygonal wheels are a widespread problem in the railway industry. Oscillation phenomena appearing at the wheelset may provide an environment where the wheel polygonization is promoted essentially. The flexibility of the wheelset was highlighted as an important influence on these phenomena in curves with a small radius of curvature at trams in recent studies. A dynamic vibration absorber applied on the wheelset may reduce oscillations at the wheelset significantly and is studied as a potential mitigation measure of wheel polygonization. A basic system model, representing a wheelset with non-driven independently rotating wheels, is used to investigate the mechanism and performance of this passive remedy. Influences of different parameter combinations of the absorber are discussed systematically. The efficiency of the dynamic vibration absorber is analysed further with a more detailed multibody system model of a two-axle tram bogie. Results reveal that an adequately tuned absorber might significantly reduce the possible development and further evolution of predominant polygonal orders. Additionally, basic guidelines for the design of the dynamic vibration absorber applied at the wheelset are pointed out.

Influences of tram characteristics on wheel polygonal wear evolution

Out-of-round railway wheels continuously excite the vehicle-track system resulting in fluctuating contact forces, creepages and contact patch dimensions. Accompanied wear may influence the evolution of railway wheel polygonization significantly. Especially in curves with a small radius of curvature, which are typical for tramway networks, considerable wear originates due to high lateral creepages. Long-time wear development studies with dominant polygonal orders reveal that some wavelengths of the wheel enlarge rapidly, whereas others are nearly unaffected or even suppressed. Therefore, fundamental research on significant influences on wheel polygonal wear evolution is required. A representative generic system model of a two-axle tram bogie is set up, and a suitable wear model is implemented to study the polygonal wear evolution at trams. It has been found that structural modes can dominate wheel polygonal wear evolution. In particular, the compliance and interaction of the wheelset axle and the resilient wheel may be essential. Evolution tendency curves are presented, and influences on the wheel polygonization are discussed. Wheel–rail contact conditions and related creepage–creep force characteristics appear to be decisive for the evolution directions and evolution speeds.

Study on Electromagnetic Relationship and Dynamic Characteristics of Superconducting Electrodynamic Maglev Train on Curved Track

This study considers an electrodynamic maglev train of the MLX01 type as the research object. Equivalent circuit models of levitation/guidance were established, and forces in different directions were solved using the energy method A field-circuit-motion coupling numerical model of a single bogie and a ground coil was established. Based on the field-circuit-motion coupling model, the various electromagnetic relationship of maglev train on curved track was analyzed. The law of the electromagnetic spring coefficient and the internal mechanism under different electromagnetic parameters was explored. Considering the coupling characteristics between the electromagnetic forces, the characteristics of the levitation force and guidance force under different standard air gaps were analyzed, and a numerical fitting analysis was performed. On this basis, the laws of levitation force and guidance force with levitation displacement and guidance displacement, as well as the characteristics of drag force with operation speed under different standard air gaps, were studied. Meanwhile, the characteristics of the guidance-drag ratio and levitation-drag ratio were analyzed. A dynamic model with 20 degrees of freedom was established based on the analysis of the geometric model of the maglev train. Taking the track irregularity as the external excitation source of the bogie, the dynamic characteristics of the bogie and vehicle body under different standard air gaps and speeds were analyzed. The effects of different suspension damping and stiffness coefficients on the vibration characteristics of a vehicle body were studied. This provides important theoretical and data support for design and dynamic analysis of superconducting electrodynamic maglev trains.

A novel dynamics model of a trailer bogie brake system and its application in stability analysis

The dynamic performance of the trailer bogie brake system is essential for the safe operation of a high-speed train during the braking process. In this work, we developed a novel ten-degree-of-freedom (ten-DOF) dynamics model of a trailer bogie brake system based on dynamic and tribological theories. The non-linear factors including disc-pad non-linear friction and wheel-rail non-linear interactions were considered. The field test results demonstrated that more intense vibrations occur at low vehicle speeds, which is also supported by numerical simulations based on the novel dynamics model. The abnormal vibration is caused by the limit cycle oscillation of the brake unit, and it leads to the instability of the whole system. To further understand the instability of the trailer bogie brake system, the equilibrium points and the linear stability of the system under different braking conditions and suspension parameters were investigated based on the Lyapunov theory. Then, the non-linear vibration response and stability of the trailer bogie brake system affected by the suspension parameters were further calculated by numerical integration methods. The results demonstrated that the mounting stiffness of the brake unit approached 3.4×107N/m and the primary suspension stiffness approached 6.0×105N/m or remained within the range of 10×105-14×105N/m, causing more violent vibrations and increased system instability. A primary suspension damping exceeding 2.4×104N·s/m was conducive to improving system stability.

Simulation of running a vehicle with a Y25 bogie on a theoretical track

This paper is focused on the simulation of a railway vehicle with a Y25 bogie running on a theoretical track and it will simulate its dynamic properties. The model was created in multi-body simulation software SIMULIA - SIMPACK. The first part mentions the basics theoretical information about the forces which acts in the bogie for example vertical load, slip or lateral forces of the wheelset. The definition of the theoretical track is listed as well. The second part deals with the basics information about technical specifications of the Y25 bogie and its usage. In the next part, the 3D model of the Y25 bogie is described. This section also describes the simulation, which is performed at different speeds. In the last part, results are evaluated and compared for each speed. Results will be suitable for further academic research and development.

Basitleştirilmiş Tekerlek/Ray Temas Modelinin ve Kalker Doğrusal Teorisinin Demiryolu Taşıtı Sinüs Hareketi Kararlılığı Açısından Değerlendirilmesi

This paper investigates the performance of a simplified wheel/rail contact modeling approach that can be implemented to dynamics analysis of railway vehicles. The scope is limited to a two-axle bogie system and the problem is investigated from the hunting instability perspective. Accordingly, a mathematical model of a two-axle bogie with elastically connected wheelsets is developed. The governing equations of the proposed four degree of freedom mathematical model are obtained. These equations are then first solved analytically by considering a simplified approach for the interfacial forces at the wheel/rail contact interface. Second, the contact forces are calculated by using Kalker’s linear theory, and the corresponding nonlinear governing equations are solved numerically. Based on the results, it is observed that the analytical and numerical solutions show a good match. Hence, it is concluded that the simplified wheel/rail contact modeling approach can represent the dynamics of the system successfully, especially when the system is in a stable state for hunting behavior. Third, the corresponding eigenvalue problem is formulated from the linear equations, and complex eigenvalues are calculated over the operational speed range of the bogie. It is observed that the natural frequencies of the system are speed-dependent, and either one or both of the wheelsets may become unstable at certain parameter sets. Finally, stability maps are generated for several parameters, and a better understanding of the effects of system parameters on the stability of two-axle bogie is obtained.

Theoretical Derivation of Gauges for Straddle-type Monorail Vehicle

The theoretical model of the straddle-type monorail vehicle bogie is set up and the function of each component is introduced. The lateral and vertical displacements of carbody when the lateral and roll motion of carbody in the same/reverse direction are attained through theoretical derivation, which can be put into the calculation of the vehicle gauge. A computational program is written to simulate the corresponding results under specific parameters. The correctness of the method to calculate the monorail vehicle gauge is verified.

CREATION OF A HIGH-PRECISION CALCULATION MODEL OF A THREE-ELEMENT STRUCTURE OF A FREIGHT CAR BOGIE

A 3D model and computational model of a freight car bogie of type 18-100 has been developed. The design model was validated in comparison with the complex of running tests. Calculations were carried out and indicators of strength and fatigue resistance were evaluated for further research. On the basis of the calculations, the probable zones of fatigue accumulation have been established.

Modelling the dynamics of an unconventional rail vehicle bogie with independently rotating wheels with the use of Boltzmann-Hamel equations

ABSTRACT The development of new technologies in public passenger transport in urban agglomerations has forced the institutions responsible for organising such transport to engage in unconventional initiatives in order to improve it and make more available, especially for elderly and disabled people. One of such initiatives consists in striving for putting into operation an increasing number of tram vehicles featuring low floors allowing people with various dysfunctions to move freely inside it and significantly facilitating entering and leaving the tram at stops. The design of such vehicles excludes the use of traditional chassis solutions since it is impossible to use wheelsets in which the wheels are connected by a rigid axle. Simulation analyses of such wheelsets come down to creating mathematical models featuring non-holonomic constraints in their description, whereas this prevents using classical equations of technical mechanics, such as Newton's equations in the construction of such models. The article describes the process of building a physical and mathematical model of an unconventional bogie with fully independent wheels with the use of Boltzmann-Hamel equations as well as exemplary results of simulation analyses of a model of such system. A design solution for this type of bogie will also be discussed.

Dynamic performance of six-axle locomotive subjected to asymmetric brake shoe forces

To research the influence of asymmetric brake shoe forces(ABSF) induced by braking failure on the dynamic performance of six-axle locomotive, the static equilibrium model of three-axle bogie and dynamic model for locomotive are established. The coupling vibration equations of axle hung motor and wheelset are derived. For the air braking, the influence mechanism of ABSF on the wheel-rail asymmetric motion and force characteristics are discussed. It can be found that if the ABSF is applied in the front wheelset, all the wheelsets move laterally in the same direction. Once the ABSF occurs in the middle or rear one, other wheelsets may move laterally towards the opposite direction. The motion amplitude and direction of all wheelsets strictly depend on the resultant moment of suspension yawing moment and brake shoe asymmetric moment. For the asymmetric braking, the free lateral gap of axle-box could increase the wheelset motion amplitude, but could not change the moving direction. In both the straight line and curve, the ABSF may lead to wheelset misaligning motion, intensify the wheel-rail lateral dynamic interaction and deteriorate wheel-rail contact state. Especially for the steering wheelsets, the asymmetric braking increases the wheelset attack angle significantly, which forms the worst braking condition.

Study on Robust Active Guidance Controller for 1:5 Scaled Bogie with Independent Rotating Wheels

This paper presents a robust active guidance controller of 1:5 scaled bogie with independent rotating wheels (IRWs) based on the Iwnicki similarity criterion in SIMPACK and MATLAB/Simulink in order to improve the stability of self-guidance and steering. Firstly, the dynamic model of bogie with IRWs is established. The active guidance steering control is realized by torque difference between the left and right wheels in the same axle that generated by four side motors. Considering the nonlinear characteristics of rail vehicles, the uncertainty of structure parameters and measurement noise, the active guidance controller using the μ-synthesis method is designed in MATLAB/Simulink by taking wheel-rail force and primary suspension force as external disturbances. The co-simulation results show that compared with the passive case, the proposed control method can significantly improve the running performance of bogie with IRWs and reduce the wheel-rail wear in both straight and curved tracks. The average wheel-rail wear number is reduced by 86% in straight track and 86.5%/99% in curved track with 5m/10m radius, respectively

Simulation and Experimental Study on the Active Stability of High-Speed Trains

An active hunting stability scheme is proposed for the high-speed trains based on frame lateral vibration control. The stability of the vehicle is improved by exerting active control force on the front and rear frames of the bogie. First, a simplified lateral vibration model of a single bogie is established to the control system design. The feedback gain matrix is obtained according to the linear quadratic optimal control theory. Then, the multibody dynamics model of the vehicle is built using SIMPACK, and the linear stability and straight running performance are analyzed under different working configurations. Finally, the active control effects are verified by a scaled roller rig. The results show that this active control scheme to improve the stability performances of vehicles through the feedback of frame vibration state is feasible.

Study on the precision of the guide control system of independent wheel

The torque ripple of permanent magnet synchronous motor vector with active control is studied in this paper. The ripple appears because of the impact of position detection and current detection, the error generated in inverter and the influence of motor ontology (magnetic chain harmonic and the cogging effect and so on). Then, the simulation dynamic model of bogie with permanent magnet synchronous motor vector control system is established with MATLAB/Simulink. The stability of bogie with steering control is studied. The relationship between the error of the motor and the precision of the control system is studied. The result shows that the existing motor does not meet the requirements of the control system.

Influence of friction wedge characteristics on lateral response and hunting of freight wagons with three-piece bogies

In this study, the nonlinear damping characteristics of friction wedges in the secondary suspension of a freight wagon are investigated considering nonsmooth unilateral contact, multiaxis motions, slip–stick conditions, and geometry of the wedges. The parameters of the contact pairs within the suspension were identified to achieve smooth and efficient numerical solutions, while ensuring adequate accuracy. A simulation model of the friction wedge was formulated and analyzed, which revealed highly nonlinear dependence on vertical, roll, and lateral motions between the bolster and the side frames. The friction wedge model was integrated into the multibody dynamic model of a three-piece bogie to study the effects of wedge properties on hunting characteristics. The resulting 114-degrees-of-freedom wagon model incorporated constraints due to side bearings, axle boxes, and the center plates, while the wheel–rail contact forces were obtained using the FASTSIM algorithm. The simulation results were obtained to study hunting properties of the wagon in terms of critical speed and the predominant oscillation frequency, and the effects of wedge friction and geometry on stability characteristics of the freight car. The results showed subcritical Hopf bifurcation of dynamic responses of the wagon. Moreover, an increase in the wedge angle, friction coefficient, and springs free length resulted in a higher critical speed.

Analysis of steering performance of differential coupling wheelset

In order to improve the curving performance of the conventional wheelset in sharp curves and resolve the steering ability problem of the independently rotating wheel in large radius curves and tangent lines, a differential coupling wheelset (DCW) was developed in this work. The DCW was composed of two independently rotating wheels (IRWs) coupled by a clutch-type limited slip differential. The differential contains a static pre-stress clutch, which could lock both sides of IRWs of the DCW to ensure a good steering performance in curves with large radius and tangent track. In contrast, the clutch could unlock the two IRWs of the DCW in a sharp curve to endue it with the characteristic of an IRW, so that the vehicles can go through the tight curve smoothly. To study the dynamic performance of the DCW, a multi-body dynamic model of single bogie with DCWs was established. The self-centering capability, hunting stability, and self-steering performance on a curved track were analyzed and then compared with those of the conventional wheelset and IRW. Finally, the effect of coupling parameters of the DCW on the dynamic performance was investigated.

219 台車傾斜-輪軸操舵の連成を考慮した鉄道台車の曲線走行時における走行安定性解析

Dynamics and running stabilities of railway bogies with a link structure are affected by coupling motion between the roll of bogies and the yaw of wheelsets, and the coupling motion depends on the offset angle of link on equilibrium position. This study constructs a model of a railway bogie, which have the link structure, to consider coupling motion between the bogie-roll and wheelsets-yaw, and investigates the traveling stability of the bogie model by time historical responses and eigenvalue analysis by using a linearized mathematical model with the link structure. First, this study shows that the proposed bogie model expresses the effects of coupling motion between bogie-roll and wheelsets-yaw. Next, this study shows that the relationship between the critical speed for stable running and the curvature radius of the track, and the effect of displacement, which is generated by moment input in the roll-direction of the bogie, to the traveling stability and safety are investigated.

PREDICTION OF GROUND VIBRATION FROM TRAINS USING SEISMIC REFLECTIVITY METHODS FOR A POROUS SOIL

Biot's model of wave propagation in porous isotropic materials is explored for predicting ground vibration from rail vehicles on vertically heterogeneous isotropic saturated soil and rock using seismic reflectivity methods combined with a multi-degree-of-freedom model of a transit vehicle bogie. A sketch of the mathematical theory, canonical results for step loads on a porous half-space, spectral responses for simple layer profiles, and an example of a prediction for rail transit vehicles are presented. The model indicates that saturation of the soil introduces excess attenuation in the vibration response of the soil, and that both pitch and roll moments in addition to vertical forces caused by the vehicle bogie may be significant sources of vibration.

A parametric study of the lateral stability of a rail bogie on a roller rig

The development of experimental facilities for rail vehicle testing is being complemented by analytical studies. The purpose of this effort has been to gain insight into the dynamics of rail vehicles in order to guide the development of roller rigs and to establish an analytical framework for the design and interpretation of tests to be conducted on roller rigs. The work described here represents an initial effort towards meeting these objectives. Parametric study results using a linear model of a freight bogie on a roller rig showed that:

Vibration of Air Suspension Bogies and Their Design

In this paper, at first the authors analyze the dynamic characteristics of the self-damped air spring on the basis of the linear theory from the standpoint of the design of air suspension bogies. The equivalent mechanical model of the self-damped air spring is obtained, which is a kind of socalled elastically supported damper systems, and the relationship among the elements of the model and the design parameters of the air spring are given. Then, using the mechanical model, both natural vibration and transient response of the air suspension bogie are analyzed numerically. As the result, it is shown that the natural frequency and the damping ratio of the self-damped air suspension bogie scarcely vary with the car body weight, and the self-damped air suspension can reduce the magnitude of the transient response compared with a conventional mechanical suspension with oil-dampers.