Trailer Wheels Research Articles

Study of the Differential Wear of Wheel Profiles on Motor Cars and Trailers of High-Speed Trains

As the operation speed of China’s high-speed trains continues to increase, a variety of complex wheel wear problems continue to emerge. Many line tests show that the differential wheel wear of the motor car and trailer car is obvious. The aim of this paper is to explore the differential wear mechanism of motor cars and trailers and their effect on dynamic performance. Firstly, this paper established a high-speed train model, which consists of two motor cars and two trailers. Then the causes of differential wear of the high-speed train from the perspective of wheel-rail contact and wheel wear were analyzed, and the Jendel wear model was used for wheel wear prediction. The wear model was verified through measured wheel wear data. Lastly, the dynamic performance of the differential wear of the high-speed train was analyzed. The results showed that the different distribution of the adhesive sliding zone in the contact patch, the different wheel-rail normal force, and tangential forces are the reasons for the differential wear. The established dynamic model and wear model can effectively predict the differential wear of the motor cars and trailer, and the maximum wear depths of the motor car and the trailer wheel were 0.886 mm and 0.721 mm. This verified the validity of the simulation model. When wheel differential wear occurs, the overall dynamic performance of the trailer is superior to that of the motor cars.

Effect of polygonal wheel on the vehicle-track dynamic interaction in turnout and its transmission to the trailer bogie wheels

The dynamic interaction between the vehicle and track is strongly influenced by out-of-round wheels and turnout rail profile geometries, which result in high-magnitude contact forces and abnormal vibrations. This study presents the dynamic response of the tram-turnout interaction due to polygonal wheel wear and analyses its transmission between the wheelsets. A three-dimensional coupled tram-turnout dynamic model was formulated, taking into account the polygonal wear on the front bogie wheelsets. Through numerical simulations, the dynamic characteristics of a tram passing through the turnout switch and crossing panels under the influence of polygonal wear were simulated. Furthermore, the impact of polygonal wear amplitudes and tram speeds on the transmission of dynamic impact forces and vibrations from the front bogie wheelset to the trailer bogie wheels are described. According to the numerical findings, when the flexible wheelset experiences polygonal wear, it can lead to substantial impact forces and vibrations as the tram moves through the turnout switch and crossing zones. Moreover, the transmission of dynamic impact forces and vibrations from the front bogie wheelset to the trailer wheels increases as the wheel wear amplitude and the vehicle speed increase.

TO DETERMINE STABILITY OF THE ROAD TRAIN WITH O1-CATEGORY TRAILER

In the work improved system of equation of plane-parallel movement of the road train with single-axle O1-category trailer. Defined lateral reactions on the vehicle and trailer wheels at body roll, wheels slip caused by body roll and also developed road train spatial mathematical model in a transverse plane. This model is used to study the road train course stability with O1-category trailer. It is shown that the spatial model of road train with no vehicle and trailer wheels inclination has the same divergent instability characteristic as the plane road train layout.

Influence of disc brake on wheel polygonal wear of high-speed train

Based on the viewpoint of friction self-excited vibration, the formation mechanism of wheel polygonal wear in high-speed train and related influence factors are studied in this study. Firstly, a field investigation of the Chengdu-Chongqing high-speed railway is conducted. The wheel polygon characteristics of the section is mastered, and the vibration frequencies excited by high-order OOR is obtained. A finite element model considering the brake system and the wheel-rail system is proposed. The unstable vibration frequency distribution and the system stability are studied by complex eigenvalue analysis. Results show that when the high-speed train runs at 300 km/h, the unstable vibration of frequency 652.8 Hz is excited. The unstable vibration will cause periodic fluctuation of wheel-rail friction work, leading to 22–23 order polygonal wear of the trailer wheel. The consistency of simulation results and Field research situation proves the correctness of the proposed method. In addition, the influence factors on the wheel polygonal wear are investigated. The pad with a high damping coefficient can effectively inhibit the 22–23order wheel polygonal wear. Increasing the Young's modulus of the pad will cause the self-excited vibration frequency increases, and the system is prone to higher-order wheel polygonal wear. The Poisson's ratio of brake pad has little effect on wheel polygonal. In addition, the brake pad structure also has a great influence on the self-excited vibration of the system. The brake pads with groove surface can decrease the self-excited vibration frequency and reduce the polygon order.

Analysing the rolling contact damage behavior of a high-speed wheel tread — A case study

This study presents the rolling contact fatigue (RCF) mechanism and damage behavior of the motor wheel and trailer wheel of a high-speed EMU operating over 1.73 million kilometers in a wind and sand environment in Northwest China. The results indicate that the profile hardness of the wheel decreases with increasing distance from the surface and finally stabilizes. Within a certain distance from the surface, the hardness of the flange root changes sharply. The surface of the tread hardens, the hardness value increases, and the variation law is similar to that of the plastic deformation of the profile. The wheel treads of the motor and trailer suffer more serious damage, such as cracks, spalling pits, dents and pitting on the surface. The profile damage is mainly characterized by long and thin layered cracks and branch cracks. Cracks located at the root of the flange and outside of the nominal circle tend to propagate toward the inside of the flange and form branch cracks and delamination cracks, which may cause multiple cracks to penetrate each other to form spalling.

The Effect of Sideslip on Jackknife Limits during Low Speed Trailer Operation

Jackknifing refers to the serious situation where a vehicle-trailer system enters a jackknife state and the vehicle and trailer eventually collide if trailer operation is not corrected. This paper considers low speed trailer maneuvering typical of trailer backing. Jackknife state limits can vary due to sideslip caused by physical interaction between the vehicle, trailer, and environment. Analysis of a kinematic model considers sideslip at the vehicle and trailer wheels. Results indicate that vehicle-trailer systems should be divided into three categories based on the ratio of hitch length and trailer tongue length, each with distinct behaviors. The Long Trailer category may have no jackknifing state while the other two categories always have states leading to jackknifing. It is found that jackknife limits, which are the boundaries between the jackknifing state and the recoverable regions, can be divided into safe and unsafe limits. The latter of which must be avoided. Simulations and physical experiments support these results and provide insight about the implications of vehicle and trailer states with slip that lead to jackknifing. Simulations also demonstrate the benefit of considering these new slip-based jackknife limits in trailer backing control.

High-speed lateral stability and trajectory tracking performance for a tractor-semitrailer with active trailer steering.

An active trailer steering (ATS) controller is investigated to improve the lateral stability and trajectory tracking performance of the tractor-semitrailer. First of all, a linear yaw-roll dynamic model of the tractor-semitrailer with steerable trailer wheels is established, and the model accuracy is verified. Then a linear quadratic regulator (LQR) for actively steering the trailer's wheels is designed. For the LQR controller, the lateral acceleration and the sideslip angle at the center of gravity (CG) of the trailer are taken as the optimization objectives, and the steering angle of the wheel on the middle axle of the trailer is set as the control input. Finally, the effectiveness of the designed controller is tested based on the co-simulation platform under the single lane-change (SLC) maneuver at the speed of 100 km/h and the double lane-change (DLC) maneuver at the speed of 80 km/h and 88km/h. Research results show that under the high-speed SLC maneuver, the designed LQR controller can significantly improves the lateral stability and trajectory tracking performance of the trailer, and cannot affect apparently the trajectory and dynamic responses of the tractor. Under the high-speed DLC maneuver, the designed controller can still make the tractor-semitrailer reach a new steady state in a short time, and improve the vehicle lateral stability and the trajectory tracking performance of the trailer at the same time.

Effect of wheelset eccentricity on the out-of-round wheel of high-speed trains

Wheelset geometric eccentricity and mass eccentricity are generally considered to be the main reasons behind the formation of the 1st order out-of-round (OOR) wear (or eccentric wear) of railway wheels. Based on finite element simulation, the relationship between wheelset geometric eccentricity and the high-order OOR wheels of high-speed trains was studied in this paper. Moreover, the reason for the phase difference between the polygonization on the left and right wheels of a railway wheelset was discussed. The results show that, when the train runs at a high speed of 237 km/h, a wheelset’s geometric eccentric value greater than 0.7 mm can lead to longitudinal creep forces on the left and right wheels to periodically reach saturation during operation, causing frictional self-excited vibrations of about 605 Hz in the wheel-rail systems; and resulting in 24th ∼ 25th order wheel polygonal wear. The phase difference between the geometric eccentric directions of the left and right wheels can cause the phase difference between the saturation states of the creep forces on these wheels, resulting in the phase difference between the 1st and 24th ∼ 25th order OOR shapes on these wheels. In addition, during the assembly of the trailer wheelset, when the phase difference between the residual static unbalance values of the wheel and brake disc is 180°, the unbalanced force couple caused by the wheelset mass eccentricity is minimal, which then slows down the formation of 1st order OOR shapes on the trailer wheels.

Soil structure response to field traffic: Effects of traction and repeated wheeling

Soil compaction caused by the use of heavy agriculture machinery in non-optimal soil conditions hampers crucial soil functions. Tyre inflation pressure and wheel load are well-known key drivers of compaction. The effects of traction and repeated wheeling are, however, not yet fully understood but may be of critical importance. We aimed to quantify the effects of traction and repeated wheeling on some soil structural properties independently in a compaction experiment conducted on a sandy loam at a soil water content near field capacity, using a tractor-trailer combination at two loads. The trailer was used in ‘standard’ and ‘offset’ steering modes, the latter referring to the mode in which measurements could be taken for the pass of a single towed and thereby passive trailer wheel (with one, two, three and six wheel passes). Penetration resistance was measured to 0.71 m depth and 100-cm3 soil cores were collected around 0.16 m depth for structural property measurements. In the offset steering mode, the measurements were made in the tractor tracks to investigate the effect of traction and in the trailer’s wheel track to investigate the effect of repeated wheeling (at 6.0 Mg static wheel load). The measurements were also collected for the standard steering configuration with the high towed load and from reference plots. Measurements on the soil cores comprised bulk density, porosity, and air permeability. We found a clear effect of traction on deformation of some soil structural properties, with no significant effects of the low drawbar pull but with substantial effects of the high drawbar pull. Reductions in air permeability and specific permeability were significant (89 % and 83 %, respectively) and indicated a densification and homogenisation of the soil. The effect of repeated wheeling was gradual and reasonably well explained by a linear fit to the number of wheel passes. After six passes with the passive wheel caused some soil structural properties to differ significantly from the reference soil, and resulted in approximately similar levels of bulk density, porosity, air permeability and specific permeability as the tractor with high drawbar pull. Still, the deformation was stronger for the single pass of the tractor with the high drawbar pull than for six repeated wheeling of the passive trailer wheel. These results highlight the substantial effect of traction on soil compaction. Yet, the mechanisms causing this deformation remain speculative until the propagation of horizontal stress through the soil profile is better understood.

Wheel wear comparison between motor car and trailer of intercity train

To analyze wheel wear discrepancy between motor car and trailer of an intercity train, a novel wheel wear rates calculation model was proposed, which was composed of the intercity train dynamics model, wheel-rail three-dimensional rolling contact FEM model and the wear model. The simulated results were contrasted with measured results in field test. The simulated results showed the motor car wheels had larger rotation rate and longitudinal creepage than the trailer wheels. Meanwhile, the motor car wheels encountered larger vertical forces and longitudinal forces from bogie because of the heavier car body and the impact of traction torque. The traction torque acting on motor car wheel could increase the slip rates in the rear part of wheel contact patch and weaken the spinning phenomenon of relative slip. Larger contact pressure and slip rates caused the higher wear rates of motor car wheel than those of trailer wheel. The overall trends of wheel wear depth in simulated and tested results were similar. And they both showed the motor car wheel encountered the more serious wear than the trailer wheel. These models can be used to study the effect of the traction characteristics curves on the wear of wheel.

Trajectory planning and robust tracking control for a class of active articulated tractor-trailer vehicle with on-axle structure

Traditional articulated vehicles exhibit poor steering performance since there exist no direct rotating moment for the underactuated trailers, which cause such vehicles nearly cannot work well in the narrow space. To overcome this shortcoming associated with the traditional articulated vehicles, an active articulated structure is proposed, in which a steering motor is introduced at the articulated joint of tractor and trailer, in addition to utilizing mecanum wheels as trailer wheels. On the basis of this structure, a coordinated control method is designed to ensure the vehicle kinematics constraints and dynamic maneuverability. The coordination control consists of two level controllers. On the level of kinematics, model predictive control (MPC) is adopted as posture controller, which can solve the non-holonomic problem of the whole active articulated tractor-trailer vehicle system; On the dynamic level, a sliding mode control (SMC) is introduced to design a dynamic controller to track the desired velocities generated online, which can increase the robustness of the system. The simulation results show that the proposed active articulated tractor-trailer vehicle system has better maneuverability compared with the traditional one, and the proposed control strategy can ensure the required control effect.

Temperatures and wear at railway tread braking: Field experiments and simulations

Field tests were carried out for a commuter train in revenue service equipped with cast iron and organic composite brake blocks. Temperatures for wheel tread, wheel web and brake blocks and wear of wheel treads and brake blocks were recorded. The measured temperatures are used for calibrating a thermal model for assessment of wheel and block temperatures. The wear of cast iron and organic composite brake blocks is estimated using simulated temperatures and temperature-dependent wear models based on pin-on-disc experiments. It is found that a wear rate adaption factor, tentatively motivated by the presence of thermoelastic instabilities at full-scale braking that cannot be found at small-scale testing, is required for producing a simulated wear that is in agreement with results from field tests. Wheel tread wear is assessed as change in flange height for both powered and trailing wheels and for the studied train it is found that the levels of annual total wear of these types of wheels are similar in magnitude. Modelling of the tread wear originating from block–wheel contact and wheel−rail contact, combined with a comparison with measured wear magnitudes, makes it possible to quantify the wear from these two tread contacts. It is found for the powered wheels that wear induced by the wheel-rail contact and the block-wheel contact have equal importance, whereas for the trailer wheels the wear emanating from the block-wheel contact is dominating.

Improving stability and lane-keeping performance for multi-articulated vehicles using vector follower control

ABSTRACT The present study discusses the effects of stability control for multi-articulated vehicles on the lane-keeping performance. Vector follower control (VFC) compensates the direction difference angles between the velocity vector at the front articulation point and the trailer using active steering of the trailer wheels. The control effects are evaluated by examining computer simulation with the driver-vehicle system, which consists of a multi-articulated vehicle model, a driver model, and VFC. VFC prevents amplification of the lateral displacements of rearward trailers, whereas the lane-keeping performance of a vehicle without VFC deteriorates. VFC does not, however, contribute to the performance of the tractor or the steering operation of the driver. A lane-keeping-assistance (LKA) system using direct yaw-moment control is applied to the tractor. The LKA system suppresses the lateral deviation of the tractor and the steering effort of the driver. In addition, the combination of VFC and the LKA system makes it possible to reduce the lateral deviations of all of the vehicles, as well as the steering effort of the driver.

3차원 노면굴곡 측정을 통한 운용지역 비포장 기동로의 가혹도 DB 구축

The profile of unpaved road is an important issue in the reliability of endurance test. Efforts on measuring 2D road profile and analyzing the severity have been continued in the study of performing reliable endurance test evaluations through reflecting the results of such measurement and analysis. However, 2D road profile has limitation in measuring the profile in the road width direction because data is obtained along the trailer wheel track. Therefore, in order to measure 3-dimensional shape of road surface and construct severity DB of 3D road profile, Changwon Proving Ground(CPG) of Agency for Defense Development(ADD) developed 3D profilometer which is composed of laser scanner, IMU, GPS, encoder and so on. This paper focuses on the analysis of unpaved road severity using 3D road profile for army operation roads. This results will be used to manage test courses severity of CPG.

Proposals for the formulation of law of control for articulated truck activated trailer hydrostatic transmission

The article is devoted to the development of scientifically based methods of creation of systems of automated adaptive control (SAAC) by “intelligent” transmissions multidrive-wheeled vehicles, such as articulated trucks with activated trailing links. The purpose of the studies is to formulate laws of control, the use of which in such SAAC should provide automatic selection in a variety of driving conditions of energy-efficient mode of power distribution between drive wheels. One of the most important issues in this case is to determine the parameters with necessary information content, which control of changes’ nature in the process of vehicle motion will allow SAAC to form control signals, ensuring keeping of the energy-optimal mode of motion in changing conditions. Obviously, these parameters should be the only ones that can be controlled during motion of articulated truck in real operation conditions by currently known and reliable methods. The article contains the results of this research obtained on the basis of the mathematical modeling of steady linear motion of articulated truck with activated trailing link, which wheels’ drive is provided by adjustable hydrostatic transmission in conditions of non-deformable bearing surface. The analysis was performed in the range of change gear ratios of trailer wheel drive when the transmission does not have interaxle power circulation. On the basis of studies the authors revealed the parameters that meet the above mentioned requirements, and also present the proposals for the formulation of control law for hydrostatic transmission of articulated truck activated trailer unit, which usage in the developed SAAC will improve energy efficiency of articulated trucks.

High Resolution Trichromatic Road Surface Scanning with a Line Scan Camera and Light Emitting Diode Lighting for Road-Kill Detection.

This paper presents a road surface scanning system that operates with a trichromatic line scan camera with light emitting diode (LED) lighting achieving road surface resolution under a millimeter. It was part of a project named Roadkills—Intelligent systems for surveying mortality of amphibians in Portuguese roads, sponsored by the Portuguese Science and Technology Foundation. A trailer was developed in order to accommodate the complete system with standalone power generation, computer image capture and recording, controlled lighting to operate day or night without disturbance, incremental encoder with 5000 pulses per revolution attached to one of the trailer wheels, under a meter Global Positioning System (GPS) localization, easy to utilize with any vehicle with a trailer towing system and focused on a complete low cost solution. The paper describes the system architecture of the developed prototype, its calibration procedure, the performed experimentation and some obtained results, along with a discussion and comparison with existing systems. Sustained operating trailer speeds of up to 30 km/h are achievable without loss of quality at 4096 pixels’ image width (1 m width of road surface) with 250 µm/pixel resolution. Higher scanning speeds can be achieved by lowering the image resolution (120 km/h with 1 mm/pixel). Computer vision algorithms are under development to operate on the captured images in order to automatically detect road-kills of amphibians.

A SIMULATION STUDY ON THE MANOEUVRABILITY OF A LARGE SIZE SEMITRAILER

As part of a research project aimed at designing the structure of a new special-purpose multi-axle semitrailer for transporting large machines and equipment, a simulation study on the manoeuvrability of the semitrailer during its passage through a tight corner was performed. The aim of this study was to determine whether the semitrailer would meet the legal requirements regarding manoeuvrability after it has been implemented for production. The simulations were carried out using a specially designed spreadsheet. The spreadsheet enabled analysis of the movements of the wheels of the tractor-trailer combination, with the assumption that they roll without skidding; it also described changes in the steering angles of trailer wheels, as well as off-tracking and corner-cutting during turning. When the geometrical parameters of the tractor and trailer were changed, the spreadsheet allowed tracing their impact on the manoeuvrability of the whole combination. This paper presents the results of the simulations and points to the desired features of a semitrailer steering system that facilitate negotiating tight corners.

The self–steering behaviour of a tractor–semi–trailer at high–speed and its control to improve lateral stability

The loss of stability by heavy highway tractor–semi–trailers can lead to serious traffic accidents. Among the contributing factors are variations in the operating conditions (e.g. different loading conditions, gusting side winds, and slippery patches on the road surface) which cannot entirely be controlled by the driver. In this paper, the behaviour of a 3–axle tractor–semi–trailer is examined from the point of view of steerability and a suitable measure of its handling characteristic is defined. On the basis of the results of this examination, some possible control methods are developed to improve the lateral stability of the tractor–semi–trailer using controlled steering of the tractor's rear wheels and of the trailer's wheels. The controller is designed using the virtual model following control law, and in the feedback loop both linear quadratic regulator (LQR) and H∞ controllers are applied.

Antecedents of Health and Safety Issues Relating to Plant Trailer Wheels

Wheel detachment from plant trailers used on public highways represents a significant health and safety hazard and major financial risk, especially for construction and utility companies that rely on these type of trailers to transport machinery such as miniexcavators or road rollers. This study uncovers the antecedents of plant trailer wheel detachment and suggests pragmatic guidance for mitigating this risk. A case study using elements of action research studies the problem in the field through direct observation and stakeholder interviews. Analysis of resulting qualitative data conceptualizes antecedents on which guidance is formulated. Risks are found to result from a combination of physical failure underpinned by inadequate human interventions and poor risk management. The primary contributions of the study are that it describes entirely novel research on trailer wheel detachment, produces new safety guidance for businesses and practitioners that operate plant trailers, and resultantly contributes to lowering the risks identified.

Research on Dynamic Transfer Performance of High-Speed Wheel Set

The parameters of high speed trailer wheel were identified by modal test using hammering method. Based on the actual measured dynamic stress data, the frequency spectrum was obtained and the transfer function was analyzed. Compared the results of the frequency spectrum analysis and the modal parameters of the wheel set, the primary frequency in frequency analysis and all the frequencies with higher amplitude in the transfer function were far from the natural frequency of the wheel set. The results show that the train is safe running on high speed line.