ABSTRACT Proper maintenance of railway tracks is essential to ensure railway safety. A track condition monitoring system was developed for the preventive maintenance of the track by installing the on-board sensing device in the in-service vehicles and monitoring the track condition by measuring the car-body acceleration. This paper describes the application of time–frequency analysis for the condition

Turnouts are among the weakest links of railway lines, but the derailment risk of vehicles passing the through route of a turnout is seldom considered. The potential factors affecting derailment are screened according to field investigations of a train derailment case at the through route of a turnout. A detailed wagon-turnout interaction model considering the non-uniform cross-sections of turnout

The calculation of the wheel–rail contact forces is one of the most difficult yet time-consuming processes in multibody system (MBS) simulations for a vehicle-track interaction system. The classical combination of the Hertzian model with the FASTSIM algorithm is the most widely used model in MBS code for railway application and the ‘exact’ solver CONTACT is seldom used due to its high computational

Braking energy recovery is one of the main technologies affecting the economic performance of an electric vehicle. To improve economy from as much recovered braking energy as possible on the premise of ensuring vehicle security is the goal of regenerative braking control strategy. However, due to the non-linear and multi-objective characteristics of hybrid braking system, finding the optimal regenerative

A direct yaw moment control (DYC) for energy-efficiency and a DYC for stability of electric vehicles (EVs) are proposed. The DYC for energy-efficiency is active during non-safety-critical cornering manoeuvres to improve the energy-efficiency of EVs. The DYC for stability is active during safety-critical manoeuvres to keep the vehicle stable. A combination of the DYC for energy-efficiency and the DYC

As the energy storage device of an electric vehicle (EV), in order to meet the mileage requirements, a battery pack always has large volume and mass and is responsible for a considerable portion of the yaw rotational inertia of the entire vehicle. As the yaw rotational inertia has a negative impact on the vehicle cornering response, a new type of EV chassis structure is proposed herein, which is equipped

This paper uses vehicle system dynamics simulations to investigate curving resistance generated from the wheel-rail interface. More than 600 simulations were conducted using a freight wagon model to investigate the implications of curve radii, vehicle speeds and track superelevation for curving resistance, as well as the changes of curving resistance with wheelset Angle of Attack (AoA) and track cant

Due to trends such as automation and new drives in commercial vehicle engineering, research is being carried out on drive concepts with individual wheel drives. In the off-road sector, these concepts offer the potential to exceed the manoeuvrability and traction performance of conventional drive trains. Mechanical drive trains are limited in this respect due to their nature (differential gears, etc

ABSTRACT This work addresses the lateral stabilisation problem of four-wheels ground vehicles. The objective is to estimate the largest state-space region such that the closed-loop vehicle lateral stability can be guaranteed. Sum-of-squares (SOS) programming technique is applied to find these maximum invariant sets while accounting for steering and yaw moment input saturations. The algorithm allows

The suspension system of maglev train has intrinsic nonlinear characteristics. The identification processing ability of nonlinear terms and the control accuracy of control algorithm have an important influence on the suspension stability of the train. Especially when the track stiffness is weak, it is easier to affect the suspension stability under the action of small deformation, resulting in the

ABSTRACT Active suspension system can drastically improve dynamic behaviours of the railway vehicle but will also introduce safety-critical issues. The fault-tolerant analysis, therefore, is essential for the design and implementation of active suspension. However, this issue did not receive enough attention so far and only few papers can be found related to the fault tolerance of active steering for

Aiming at the problem of improving driving comfort under the condition of ensuring driving safety and limited suspension travel, this paper proposes a sliding mode adaptive controller suitable for strong disturbance action. Considering the nonlinear characteristics of the hydraulic actuator, a one-half vehicle suspension model with uncertain parameters and external disturbances is established. In the

ABSTRACT Active wheelset steering promises an attractive cost–benefit ratio and is highly likely to be implemented in the future. Previous studies investigated the steering effect simply through a wear index like wear number. However, a wear index cannot predict how much the material removal on wheels can be reduced, and it is unable to reveal the wear pattern. This paper builds an iterative wear model

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

The air spring is the main part of the secondary suspension of passenger railway vehicles. The aim of this paper is to review existing modelling techniques for air springs in order to check if challenges set in the past decade for available models have been met. The advantages and disadvantages of different air spring models (phenomenological/mechanical, thermodynamic, analytic, FEM) are summarised

The levitation bogie of the TR-series maglev vehicle is redesigned by adding an intermediate buffer layer between the levitationbogie and the levitation module to improve the curve negotiation capacity of the high-speed maglev vehicle and reduce the vertical coupleddynamic effect of the vehicle and the track beam. As the existing TR08 maglev vehicle dynamic model has been verified by experiments, anew

The roll centre (RC) is a core parameter for vehicle lateral dynamics and control, which can be obtained via suspension geometry configuration or suspension kinematics and compliance (K&C) test. However, these methodologies are used for laboratory tests and are suitable at low lateral acceleration. In other words, the RC is hard to measure directly while the vehicle is running on the road. In this

In passenger cars active suspensions have been traditionally used to enhance comfort through body control, and handling through the reduction of the tyre load variations induced by road irregularities. However, active suspensions can also be designed to track a desired yaw rate profile through the control of the anti-roll moment distribution between the front and rear axles. The effect of the anti-roll

The present paper introduces a tire/road friction prediction tool based on modelling the tire/road contact as dynamic, viscoelastic, rough, and lubricated. The tool takes into account a considerable part of influent parameters related to tire, road, contaminant, and contact operating conditions: For the tire, the tool takes into account its geometry and rubber material behaviour. For the road, the

To study the impact coefficient of track beams due to moving suspended monorail vehicles under the bridge deck, this paper presents a vehicle-bridge dynamic model based on the rigid-flexible coupling method. Finite element method is used to establish the bridge model, and the vehicle is simulated as a multi-body dynamic model The mechanical characteristics of running tire are precisely modelled and

A mechatronic rail vehicle with reduced tare weight, two axles and only one level of suspension is proposed with the objective of reducing investment and maintenance costs. A wheelset to carbody connection frame in composite material will be used both as structural and as suspension element. Active control is introduced to steer the wheelsets and improve the curving performance. A feedforward control

An in-depth understanding of car-body vibration characteristics is the key to developing more reasonable operational safety and discomfort evaluation indicators. However, few scholars or research institutions have focused on this topic, and the car-body vibration characteristics that are caused by different complex aerodynamic factors are not clear. Therefore, in this study, different train car-body

This paper studies the influence of lateral and local rail deformation on the train–track interaction dynamics in high-speed railways. While the traditional method ignores the curvature of a laterally and locally deformed rail and treats it as a straight rail with an additional displacement, this paper considers the laterally and locally deformed rail as a curved rail and models the train–track interaction

(2020). Vehicle-Track Coupled Dynamics. Vehicle System Dynamics. Ahead of Print.

In order to improve the passing performance of the diverging route of a turnout, a tentative idea of applying a superelevation transition on the guide curve is proposed. Based on the parameters of 1:42 turnout, the guide curve is modified with different combinations of horizontal alignment and superelevation. Superelevation is implemented by the way of decreasing the elevation of the inner rail. A

This paper analyses the performance benefit due to electrical overloading of battery pack and electric motors in battery electric vehicles with four wheel-independent drives. The performance enhancement is quantified by relative lap time improvements which are computed using minimum-time optimal control. Additionally, a concurrent optimisation is performed which provides the optimal gear ratios for

In this paper, a coupling longitudinal-vertical dynamic model of a wheeled vehicle under off-road conditions is established. In the present model, the vehicle’s travelling velocity changes as the vehicle heaves under ground excitations. The relative movements between the vehicle body and the wheels in both longitudinal and vertical directions are taken into account. From this model, the vehicle’s vertical

In this paper, a hierarchical optimization strategy for an ambulance with a supine human body model is proposed to improve suspension performance, where the ride comfort of both patients and paramedics and the road holding of the ambulance vehicle are particularly focused. An ambulance model integrating a hydraulically interconnected suspension system and a stretcher-human body model is developed first

The dynamic model of the automobile shimmy system considering the sinusoidal road roughness excitation is established, and the response characteristic of the shimmy system is investigated with numerical simulations. Based on the complexification-averaging (CX-A) method, the slow flow equations of the shimmy system are obtained, and the shimmy angle of the front wheel is available on the basis of the

Electrification of road vehicle powertrains involves significant re-design and re-sizing of foundation brakes. Both the usage and the size of hydraulic brake systems can particularly be reduced thanks to the contribution of regenerative braking torque supplied by electric motors, thus reducing cost and weight. In this work, a multi-objective optimal computer-aided engineering (CAE) methodology is proposed

When a four-wheel-drive hybrid electric vehicle (HEV) with dual clutch transmission (DCT) is decelerating while turning, the vehicle often transits from front-wheel hybrid mode to electric mode of the rear hub motors, in order to improve the energy efficiency. However, the mode transition process is accompanied by the driving torque front-to-rear axis conversion and the wheel load transfer. And the

Understanding the relationship between car-body vibration and train aerodynamic forces is very important for developing a reasonable operation plan when the train passes through the complex terrain under strong wind conditions. In this study, car-body vibration under strong wind conditions was initially investigated with a full-scale test. Then the train aerodynamic forces for different rotation configurations

Railway bogies of the Y25 family are the most common type of freight bogies used in Europe. However, this family of bogies presents poor curving performance and a derailment history. Although numerical simulations are a powerful tool to study railway dynamics, derailment scenarios involve complex operational and vehicle conditions that increase the multivariate aspect of the problem. Thus, simulating

Plenty of studies focused on single-direction active suspensions on railway vehicles; at least four actuators per vehicle are needed forconventional active secondary suspensions in both lateral and vertical directions, leading to a sharp increase in costs and reduction inreliability. This paper proposes a novel configuration, lateral-vertical coupled (LVC) active secondary suspension, with only two

The wheel-rail rolling contact finite element model has been generally considered to be a better choice for solving the high-frequency wheel-rail responses and local stress/strain states, compared to the traditional multi-body dynamics model. However, some thorny issues in the wheel-rail finite element analysis need to be solved or avoided, such as difficulties in geometry modelling especially for

A common phenomenon of rail corrugation and its spatial distribution are observed in high-speed rail according to the overall and local field investigations, in which the rail corrugation with a wavelength of 100–300 mm and a depth of 0.01–0.05 mm normally occurs on both the rails in the sharp gradient sections of the high-speed rail. Then, a relevant simulation model of the wheelset–track system supported

In railway heavy haul transportation, the wheel-rail contact interaction has a strong influence on the performance of the entire system. According to the vehicle longitudinal movement conditions - straight/curved tracks and travel speed, contact interaction takes place on different portions along the wheel/rail geometric profiles. Determining wheel/rail contact patches is fundamental both for vehicle

Characteristic values are essential for the design and assessment of driving dynamics during the early stages of the development process of passenger cars. Compared to other aspects of vehicle dynamics however, the relationship between measurable parameters and the subjective perception of vehicle roll dynamics has not been researched extensively. In this paper, a study is presented in which several

Serious wheel polygonal wear usually causes drastic wheel/rail interactions, which threats the running safety of railway vehicles. This paper presents an investigation into the effect of polygonal wear of heavy-haul locomotive wheels on the dynamic performance and wheel/rail interactions through extensive on-site tests and numerical simulations, in which a special attention is paid to locomotive vibrations

Differential steering is an emerging steering concept based on traction force differences between left and right sides of vehicles equipped with independently actuated wheels. Actually, this concept is only used to support classical vehicle designs utilising rack and pinion steering components. However, it may fully substitute such devices to reduce complexity and cut down costs. Since we do not have

To improve the integration of active radial systems of railway vehicles and their adaptability to the vehicle structure, this paper proposes an active radial actuation system based on flexible elastomers. The execution unit of the system has a compact layout and can be embedded in an axle box. The core functional component is a flexible elastic oil-filled rubber bladder, which has active radial actuating

Locomotive-track interaction is a multidimensional task because it goes in many directions depending on the aim of the investigation. One such direction relates to wheel or track damage produced by traction and braking of locomotives under different train operational scenarios. The best option for performing wheel or track damage studies is to use the Exact theory developed by Kalker directly in the

This study aims to provide quantitative insight into the sensitivity of tyre parameters on the performance of the anti-lock braking system (ABS) control algorithms. Unlike conventional sensitivity analysis methods, which depend on a few test cases, in this study, Magic Formula (MF) 6.1 tyre model is used to generate a comprehensive set of thousands of virtual tyres that encompasses all possible combinations

Catenaries are large cable structures which transmit electric current to trains through sliding contact with a pantograph. The finite element method is widely used to model this dynamic interaction problem and obtain the contact force between the pantograph and the catenary. As an alternative, analytical models can also be used to study catenary dynamics, although they require certain simplifications

Tyre, being the most important component of any vehicle, has been studied to quite a lot since its invention. Although, many different tyre models are being used for analysing steady-state tyre forces, there is not enough emphasis on including the transient response in detail. Although, steady state tyre model can be helpful in understanding handling characteristics of the vehicle, it fails when a

Equivalent conicity is an equivalent mean parameter for reflecting the effects of lateral wheel-rail forces on passenger comfort on trains. Based on the asymmetry of the variable cross-section rails in the turnout zone, this paper views the equivalent conicity of a wheelset in the turnout zone as an equivalent conicity of a wheelset in which the wheels match all constant-section asymmetrical rails

To improve the understanding of wheel/rail contact behaviour and damage mechanisms in turnouts, the 3D explicit finite element model of a wheelset rolling over a switch is introduced. This takes into account the arbitrary geometrical profile of the wheel-rail system, the relative motion between switch/stock rail, the nonlinear materials and actual moving postures of the wheelset. Precise frictional

Optimal control is used to study the management of tyre performance for a Formula One car. Tyre friction is compromised by accumulated wear and operation outside the tyre design temperature window – inappropriate thermal operation accelerates tyre wear. In this study tyre wear is modelled as a function of the tyre surface temperature and the power dissipated at the road contact. The tyre's frictional

This paper considers the interaction between a train mounted pantograph and a railway overhead line, presenting results that could be used to reduce the cost of installing overhead electrification, for example, by reducing the need for expensive bridge reconstruction. Ideally, overhead wires would run at a constant height parallel to the track, however, gradients are often unavoidable due to clearance

The longitudinal distance between the centre pivot and the centre of end bogie significantly affects the wheelset lateral force of the outer and inner wheelset. Whether the centre pivot of end bogie of articulated train needs to be offset, and how to set the offset distance, research is still lacking. Taking this as a starting point, this study utilised wheelset lateral force factor to discuss the

Metro trains often encounter the problem of wheel flange wear when they pass through sharp curves, especially for the poor wheel–rail profile matching or lack of lubrication, evidently increasing the maintenance and replacement costs for wheelsets and rails. Based on the field investigation and numerical simulation, the cause of severe flange wear of the original S1002 wheel profile on a Chinese metro

The APM 300 running gear structure follows the structural design of the automobile steering drive axle; therefore, the lateral stiffness of the suspension system is considerable, resulting in poor lateral ride comfort. To improve the lateral ride comfort of the vehicle, this paper proposed a new type of running gear called single air spring running gear (SARG), and according to the original loading

In this study, the aerodynamic forces on a stationary train and moving train as well as the flow fields at the bottom of the trains were compared and analysed. In addition, the numerical algorithm used in the simulation with a stationary train was verified by wind tunnel experimental data. The results show that the distribution law of the drag of the train (without bogie) and bogies is evidently altered

A rigid-flexible coupled train-seat-human model was developed for studying ride comfort of rail vehicles. The weighted acceleration r.m.s. value at the seat pan was used for assessing ride comfort. The contribution of different modes of the carbody to ride comfort was defined from the perspective of power spectral density. The role of first bending mode was more important than other bending modes when

Railway vehicles frequently have derailed during major earthquakes. Although a probabilistic approach based on fragility analysis was established in structural engineering, it has never been applied to railway vehicles. Thus, the aim of this study was to select optimal intensity measures (IMs) and develop fragility curves for the derailment of vehicles. Eight commonly seen IMs were examined to determine

Train derailment can cause not only damage to the train itself but also secondary damage to surrounding structures. For this reason, guard rails are commonly used to prevent secondary damage caused by derailed trains on high-risk lines. In this paper, a 3D vehicle-track dynamics simulation model and a collision contact model were used to investigate the post-derailment dynamic behaviours of the train

Track stiffness irregularity is superficially invisible on rail surface, while causes dynamical impact and track deformation when trains running through. Aiming at this issue, this work presents an investigation on the influence of track stiffness on dynamic behaviours of the high-speed vehicle–track–bridge dynamic system. Primarily, a determination method of track stiffness irregularity is analytically

When designing articulated tractor-trailer systems, engineers should take care to contrast some undesired phenomena associated with the lateral dynamics: the path off-tracking, namely the trajectory deviation of the points of the two units compared to the midpoint of the tractor fore; the rearward amplification of the transverse acceleration. The off-tracking may lead the vehicle tail to invade the

A long-term tracking test was performed on a newly designed high-speed train with the nominal speed of 250 km/h. The wheel roughness and structural vibration were both recorded during two re-profiling cycles. The 3rd order polygonal wear was observed in the early stage. The vibration of the axlebox can be aggravated even at lower speed when the passing frequency of polygonal wear approaches the P2

Although a passive independently-rotating wheel-pair (IRW) is not well suited for curve negotiation due to an inability to provide the necessary steering, an active IRW system offers the potential to realise perfect curving with a satisfactory running stability. Simple control solutions to realise automatic steering and stability of the IRW system are proposed in this paper. In this control approach