Tire Contact Research Articles

An in-wheel sensor for monitoring tire-terrain interaction: Development and laboratory testing

An in-wheel sensor system was developed to monitor the deflection and shape of a tire that it is operating on and interacting with terrain. Three ultrasonic sensors were mounted to rotate with the wheel rim to measure radial distance to the inner tire surface at the mid-plane and at two equidistant lateral planes of the tire. This study describes evaluation of the sensor system using a laboratory drum-test machine which drives the tire over a wide range of speeds at different normal tire loads and inflation pressures. Signal processing methods are described for extracting characteristic measures of the tire contact and shape geometry which can be determined from measurements of inner tire surface deflection. The measurement of contact length compared well with results measured using other methods and reported in the literature. Additional tire shape metrics are defined that may be useful for informing how automated adjustments can be made to inflation pressure by central tire inflation pressure systems. In most of the test cases, the three sensors showed no significant lateral variation in measured deflections, as expected for testing on a rigid drum.

Estimation of Tire–Road Contact Features Using Strain-Based Intelligent Tire

ABSTRACT Sensors attached inside the tire near the contact area can provide crucial information on contact characteristics, e.g., slip, forces, and deformation of tires. Vehicle control systems such as antilock braking systems (ABS) and vehicle-stability control (VSC) can be enhanced by leveraging this information, since control algorithms can be updated based on directly measured parameters from intelligent tires rather than estimated parameters based on complex vehicle dynamics and on-board sensor measurement. Moreover, tire characteristics can be investigated by scrutinizing the sensor measurements on the basis of well-defined physical theories on tire mechanics. In this article, estimations of tire contact features have been studied with the circumferential strains measured inside the tire. These parameters were imported to physical tire models to finally predict lateral force, which plays the crucial role in algorithms of vehicle control systems, as well as in analysis of tire performance.

Analysis of the influence of assembly electric motors in wheels on behaviour of vehicle rear suspension system

The increase in interest in electric vehicles is associated primarily with the actions of states that seek to sell new vehicles with low emissions of harmful compounds into the atmosphere. This is codified by emission standards. One of the solutions of the exhaust emission problem is the use of the electric drive (assuming that electricity comes from renewable sources). The electric drive system can be developed in several ways, depending on how the drive torque is transmitted: by gears or directly to each wheel. These constructional solutions affect the largeness of unsprung masses and require proper selection of vehicle suspensions. Series of tests and simulations has been carried out to verify the mathematical model proposed for the rear suspension system with electric motors mounted in the wheels. The simulation model has been prepared in the MSC.Adams package. This model was (tuned) verified by comparison the dynamic response of the system with the experimental results. The verified model was used to analyse the impact of the shock absorber damping characteristics on tire deflection and contact forces acting between the road and tire.

Multi-wheel gear loading effect on load-induced failure potential of airfield flexible pavement

ABSTRACTThis study aimed to investigate the effect of multi-wheel loading gear configuration on loading-induced failure potential of airfield flexible pavements. Field response testing was conducted in the National Airport Pavement Test Facility (NAPTF) using different multi-wheel gear configurations. Three-dimensional (3-D) finite element (FE) models were developed to simulate multi-wheel loading along with non-uniform tyre contact stresses. The 3-D FE models were validated by tensile strains measured from response testing. The effects of wheel loading configurations and magnitudes on different strains responses were compared for two pavement sections with different asphalt layer thicknesses. Analysis results showed that six-wheel gear configuration caused the greater pavement responses. The critical shear strains were found greater than critical tensile strains at the same loading condition and pavement structure, especially for thick asphalt pavements. This is consistent with top-down cracks observed at field sections after traffic testing. On the other hand, shear strains increase more rapidly as the load level increases as compared to tensile strains; while thin asphalt layer is more sensitive to loading magnitude as compared to thick asphalt layer. The multi-wheel effect on fatigue life is more significant for thick pavement due to the load superposition effect under different wheels.

Experimental Study of Winter Tyre Usage According to Tread Depth and Temperature in Vehicle Braking Performance

The study was aimed at identifying the problems of using winter tyres according to the vehicle braking performance. Due to the common problem of using second-hand winter tyres during the summer season, the tyre tread depth and temperature were chosen as the main indicators of the study. The winter mix tyres are distinguished by the suitability for operation at low temperatures; however, if the operation of such tyres is extended during the warm season, high ambient temperature and the road pavement temperature during extreme braking deteriorate the tyre contact properties. This article presents the results of thermodynamic measurements of the vehicle’s braking performance and the tread surface of abruptly braked winter tyre. To determine the relative slip at different ambient temperatures and the tread depth of the braked tyre, the dynamic wheel radius and the angular velocity were measured during the study. The results obtained according to the main physical parameters determining the tyre contact present the objective assessment of the negative use of winter tyres during the warm season. Conclusions are useful in not only promoting the responsible choice of the tyre type, but also introduction of potential limitations and development of subsequent tyre and automotive safety, in order to avoid traffic accidents.

Integrated Adaptive Cruise Control with Weight Coefficient Self-Tuning Strategy

This paper presents a novel multi-objective coordinated adaptive cruise control (ACC) algorithm based on a model predictive control (MPC) framework which can comprehensively address issues regarding longitudinal car-following performance, lateral stability, as well as vehicle safety. During the car-following, vehicle dynamics, illustrating the forces acting on the tire contact patches, are established. To simplify the tightly coupled dynamics system, a state-feedback based disturbance decoupling method is employed, by which longitudinal and lateral dynamics can be completely decoupled. Furthermore, the traditional MPC control with a constant weight matrix will probably not be able to solve time-varying multi-objective coordinated optimization issues, especially in transient scenarios. A weight coefficient self-tuning strategy is therefore suggested by which the weight coefficient for each sub-objective can be adjusted automatically with the change of traffic scenarios, accordingly improving the overall car-following performance. The simulations show that the control algorithm utilizing the suggested self-tuning strategy reaps significant benefits in terms of longitudinal car-following performance, while at the same time maintaining a small lateral stability error range.

Potential of three-dimensional footprint mold in investigating the effect of tractor tire contact volume changes on rolling resistance

In the present study a method is developed to estimate the three-dimensional (3D) footprint of pneumatic agricultural tires based on molding the tire footprint by liquid plaster and converting these molds to three-dimensional models using a 3D scanner. A Goodyear 12.4–28, 6 ply tractor drive tire was operated on a clay loam soil in a soil bin under three vertical loads, using three inflation pressures and three soil moisture contents at a constant forward speed of 0.45 ms-1. The results showed the rut depth and contact volume increased by increasing the vertical load and inflation pressure and soil moisture content. Contact volume was increased by increasing the vertical load, inflation pressure, and soil moisture content. A multiple regression model was presented with a coefficient of determination (R2) of 0.88 to predict the contact volume based on vertical load, inflation pressure, and soil moisture content. Finally, a univariate regression model was presented to predict the rolling resistance based on the contact volume with a relatively high R2 of 0.93. It was also found that in deformable surfaces, vertical penetration and soil contact volume are the main reasons for the increase in rolling resistance.

An investigation towards intelligent tyres using finite element analysis

ABSTRACTIntelligent tyres have the potential to be widely used to enhance the safety of road transportation systems by providing an estimation of the road surface friction, tyre load and several other important characteristics. Since the tyre–road contact characteristics play an important role in stability and control of vehicles under severe manoeuvers, tyre interaction with the road surface needs to be evaluated in the contact patch region. In this research, a finite element model is implemented to investigate the effects of different parameters, including vehicle velocity and normal load, on the projected contact patch area. Furthermore, a tyre with a tri-axial accelerometer attached to its inner-liner is tested on different road surfaces with different contact frictions and at different loading conditions. To validate the model, the radial and circumferential accelerations obtained from the simulation are compared with the experimental results. The effects of velocity, normal load and coefficient of friction on the contact patch area are investigated and it is concluded that the circumferential component of acceleration is the key factor for estimating the tyre contact patch length.

Tyre–pavement contact stress distribution considering tyre types

Tyre–pavement contact stress distribution has a significant effect on mechanical responses in thin asphalt pavements and responses at near-surface of thick asphalt pavements. To achieve a more accurate tyre–pavement contact stress distribution considering tyre types, tyre loads and tyre inflation pressures for pavement design and analysis, three-dimensional (3D) finite element (FE) tyre–pavement models were developed. Two common tyre types (bias ply tyre and radial tyre) were considered in the models. Then, models were verified through the comparison between the predicted and measured tyre contact stresses. Excellent agreement between predicted and measured contact stresses was achieved. Then, the contact stress distributions between different tyres and pavement were analysed under different tyre loads and tyre inflation pressures combinations (nine working conditions). Results indicated that with the increase of vertical load, the location of maximum contact stress between bias ply tyre and pavement changed from inside to outside of tread while the maximum contact stress between radial tyre and pavement always appeared in the centre of tread. And under a same working condition, the maximum contact stress between radial tyre and pavement was larger than that between bias ply tyre and pavement. Besides, in the lateral direction, the variation range of the contact stresses under different ribs of a bias ply tyre was less than that of a radial tyre.

A novel approach to tire parameter identification

Since they are believed to provide more reliable and accurate tire contact parameters, intelligent tires have been widely studied for the purpose of the performance enhancement of the vehicle control systems such as anti-lock breaking system and the electronic stability program. Moreover, it is also expected that intelligent tires can be utilized to analyze tire dynamic response, taking into consideration that the measurements from the sensors inside the tire would contain considerable information on tire behavior in real driving scenarios. In this work, the tire physical characteristics related to in-plane dynamics of the tire, such as stiffness of the belt and sidewall and contact pressure distribution, were identified based on the combination of strain measurements and a flexible ring tire model. The radial deformation of the tread band was directly obtained from strain measurements based on the strain-deformation relationship. Tire parameters were identified by fitting the radial deformations from the flexible ring model to those derived from strain measurements. This approach removed the complex and repeated procedure to satisfy the contact constraints between the tread and the road surface in the traditional ring model. For validation purposes, circumferential strains were measured for three different tires on a Flat-Trac indoor test rig. And then, circumferential contact pressures and tire parameters were estimated based on these measurements. Identification using only model-based methods was conducted and comparison was made to the measured contact patch shapes. The comparison among identification methods and measurements shows good agreement. The proposed method of utilizing intelligent tire fused with physical tire model is expected to provide another tool to investigate tire characteristics. Moreover, tire properties identified using intelligent tires could be more closely linked to vehicle performance.

Robustness and Applicability of a Model-Based Tire State Estimator for an Intelligent Tire

ABSTRACT Tire states can be estimated by measuring the tire contact patch shape as it varies with vertical load, longitudinal and lateral slip, and so on. In this study, a miniature triaxial accelerometer is used to measure the centripetal accelerations at the tire inner liner. A tire state estimator (TSE) algorithm is developed to transform the measured accelerations to actual tire states, in this case vertical load. The approach used for the TSE is the extended Kalman filter (EKF), but an additional peak detection algorithm is used to synchronize the simulation model with the measurement signal before applying the EKF. The simulation model used in the EKF is an empirical model that describes the basic shape of the centripetal acceleration signal. The applicability of the estimator is assessed by considering the accuracy and robustness for several tire operating conditions: vertical load, velocity, inflation pressure, sideslip, camber, and braking. It is concluded that the TSE exhibits accurate vertical load estimation even in cases of varying load and velocity. Further, it is concluded that the vertical load estimation is robust for (pure) camber changes and (pure) longitudinal force disturbances. For relatively high lateral forces as result of sideslip, the estimation error is larger. The current estimator appears to be not robust for inflation pressure changes, but this can be solved by adding an inflation pressure sensor. Similarly, extension of the estimator to estimate lateral force by adding a second accelerometer not only provides an additional state but also adds the possibility of improving the vertical load estimation. Finally, it is demonstrated that the TSE is able to perform in real time and shows fast convergence capabilities for cases in which the initial vertical load and/or sensor position are unknown or when moving away from situations in which the signal-to-noise ratio is poor.

Discrete modeling of sand–tire mixture considering grain-scale deformability

Mixing sand or soil with small pieces of tire is common practice in civil engineering applications. Although the properties of the soil are changed, it is environmentally friendly and sometimes economical. Nevertheless, the mechanical behavior of such mixtures is still not fully understood and more numerical investigations are required. This paper presents a novel approach for the modeling of sand–tire mixtures based on the discrete element method. The sand grains are represented by rigid agglomerates whereas the tire grains are represented by deformable agglomerates. The approach considers both grain shape and deformability. The micromechanical parameters of the contact law are calibrated based on experimental results from the literature. The effects of tire content and confining pressure on the stress–strain response are investigated in detail by performing numerical triaxial compression tests. The main results indicate that both strength and stiffness of the samples decrease with increasing tire content. A tire contact of 40% is identified as the boundary between rubber-like and sand-like behavior.

Analisis tekanan udara, sudut slip dan ukuran lebar ban tipe radial terhadap rolling resistance dengan metode taguchi

Rolling resistance is one of the main factors affecting the fuel efficiency of a vehicle. Rolling resistance is resistance to the wheels that will and has been rolled due to the force of friction between the wheels with the road surface of the wheel, due to the deformation process on the tire structure, contact area and road surface. Radial tires are tires where the reinforcing fibers on the carcass are arranged radially, have a greater ability to withstand lateral forces and generally have high ratio aspect ratio, widht smaller than the bias tires. The taguchi method is a new methodology in engineering aimed at improving product and process quality, minimizing cost and time. The purpose of this research is to know the air pressure influence, slip angle and tire width to rolling resistance. The research was conducted experimentally by using taguchi method. The result showed that the highest rolling resistance force accurred at a combination of air pressure of 175 kPa, 9o wheel slip angle and 90 mm widht of tire size of 36.914 N. While the smallest rolling resistance was obtained with a combination of parameters at the air pressure level of 325 kPa, slip angle 1o and the size of the 70 mm tire widht of 11.511 N at 350 rpm and normal load 580 N. From the result it can be concluded that the change in the level of the three air pressure parameters, the slip angle and size of tire width can affect the rolling resistance value.

Analisis tekanan udara, sudut slip dan ukuran lebar ban tipe radial terhadap rolling resistance dengan metode taguchi

Rolling resistance is one of the main factors affecting the fuel efficiency of a vehicle. Rolling resistance is resistance to the wheels that will and has been rolled due to the force of friction between the wheels with the road surface of the wheel, due to the deformation process on the tire structure, contact area and road surface. Radial tires are tires where the reinforcing fibers on the carcass are arranged radially, have a greater ability to withstand lateral forces and generally have high ratio aspect ratio, widht smaller than the bias tires. The taguchi method is a new methodology in engineering aimed at improving product and process quality, minimizing cost and time. The purpose of this research is to know the air pressure influence, slip angle and tire width to rolling resistance. The research was conducted experimentally by using taguchi method. The result showed that the highest rolling resistance force accurred at a combination of air pressure of 175 kPa, 9o wheel slip angle and 90 mm widht of tire size of 36.914 N. While the smallest rolling resistance was obtained with a combination of parameters at the air pressure level of 325 kPa, slip angle 1o and the size of the 70 mm tire widht of 11.511 N at 350 rpm and normal load 580 N. From the result it can be concluded that the change in the level of the three air pressure parameters, the slip angle and size of tire width can affect the rolling resistance value.

Comparative analysis of strategies for a semi-active suspension of a ¼ vehicle

The vehicle suspension isolates the chassis from road irregularities, reacting to forces produced by the tires and the braking torques, always keeping the road tire contact, providing stability and safety. Stability and safety are two antagonistic characteristics in suspension design, when improving one the other is impaired and vice versa. The semi-active suspension is a type of vehicle suspension that can change its stiffness and/or damping in real time depending on the vehicle response to the actual road profile. The On-Off semi-active suspension changes its damping coefficient between two fixed limit values. This work proposes an On-Off semi-active suspension model, in which the damping coefficient changes its values considering the road profile function frequency. A control strategy is proposed in a way to improve performance keeping the same simplicity, without any structural change of the semi-active suspension. On the proposed control strategy one of the damping coefficients is obtained through the linear quadratic regulator (LQR) algorithm, with the aim to set the coefficient from the gain matrix associated to the velocity of the suspended mass. This model is compared to anothers found in literature.

Vibration Characteristics Analysis of Convalescent‐Wheelchair Robots Equipped with Dynamic Absorbers

To provide a theoretical guidance for the vibration isolation design, the vibration responses characteristics for the convalescent‐wheelchair robot with DA (dynamic absorber) undergoing the random road were revealed. Firstly, the vibration model of the convalescent‐wheelchair system with DA was created. The frequency response functions of the road excitation velocity to the convalescent acceleration, the wheelchair body acceleration, and the tire dynamic deflection were deduced. Then, the numerical calculation method of the PSD (power spectral density) and the RMS (root mean square) responses were proposed. Thirdly, the vibration isolation performances of the wheelchair robot with DA and without DA were compared. Finally, the sensitivity analysis of the vibration responses to the mass ratios, the damping ratios, and the natural frequencies was carried out to reveal the effects of the parameters on the vibration responses. The results show that the DA can partly suppress the vibration of the convalescent and the wheelchair body, especially in the resonance area of the wheelchair body. However, the DA cannot successfully improve the tire contact behavior.

Improved Friction Model of the Aviation Tyre Contact with the Landing Strip

It is proposed further development of the theory of multi-component dry friction which consists in presenting a more convenient form of the coupled friction models for the problems of the aviation pneumatics dynamics. The constructed dry friction theory allows one not only the analytical solution of model problems but also can be applied in the engineering practice, for instance to predict the shimmy if the sliding and spinning cannot be neglected.

Study of the vibrational behaviour of the components of a car suspension

The paper presents a study of the vibrational behaviour of a car suspension in the frequency range from 50 to 200 Hz. The vehicle has a torsion spring suspension. The aim of the study is to provide a numerical approach, which evaluates the impact of the tyre vibration characteristics and the elastic properties of suspension elements on the vibrational behaviour of the “tyre-suspension-body” system. The object of the study are the elements of the suspension – stub-axle, upper and lower suspension arms, strut rod, torsion bar and others. The suspension is equipped with pneumatic tyres with different vibration characteristics. Laboratory experiments are done. The tyre contact patch is disturbed by harmonic force. The accelerations of the wheel axle and specific points of the suspension are obtained. A numerical model of the system is created by using the Finite Element Method available in SolidWorks Simulation software. The model allows to determinate the accelerations at different points of the suspension. The results of the experimental and theoretical studies are compared. The values obtained in the two studies are similar.

Relative Pavement Performance for Dual and Wide-Based Tire Assemblies Using a Finite Element Method

Abstract There is a need to assess the realistic tire contact pressure created by a tire in contact with a pavement. The contact pressure is a function of tire type, axle loading, and tire inflation pressure (TiP). The research carried out considered dual tire and wide-based tire assemblies across a range of axle loading and TiP. These contact pressures were incorporated into a finite element package (CAPA-3D) and modelled on a simple pavement structure. The strains from this modelling were sorted to produce key strains associated with the mechanisms of surface distress, near surface distress, deep asphalt distress, and the subgrade. The main distress mechanisms were top down cracking, asphalt cracking/rutting, bottom-up fatigue cracking, and subgrade rutting. This gave a method to fairly compare the dual and wide-based tire assemblies with the same axle loading and TiP. The analysis gave interesting results for the different distress mechanisms of the pavement. The wide-based tire gives consistently higher shear strains for all the areas of distress investigated. There is great variation in surface and near surface shear strains due to the different combinations of axle loading and TiP. It is clear that the wide-based tire is a more damaging tire for all combinations of TiP and axle loading. It is also apparent that how these factors interact has a great influence on the damaging potential of a tire.

3D FEM analysis of flexible base asphalt pavement structure under non-uniform tyre contact pressure

Circular uniform pressure distribution has been traditionally utilised in the analysis of mechanical-based asphalt pavement. However, both the magnitude along tyre width and length shows non-uniformity. Thus, EverStressFE, a 3D software package, was applied to establish a numerical model of the flexible base asphalt pavement structure under non-uniform vertical tyre contact pressure. Comparisons were made among the distribution of non-uniformity and uniformity on pavement surface deflection, pavement structure shear strain, the tensile strain at the bottom of the asphalt concrete surface layer and the vertical compressive strain on the top of the subgrade. The control index on the design life of the pavement under the non-uniform vertical contact pressure was discussed. The results show that, compared with uniform distribution, convex non-uniform distribution produces larger deflection on the pavement surface and maximum tensile strain at the bottom of the asphalt concrete surface layer, while the concave one generates larger shear strain on the pavement structure. Meanwhile, the non-uniform distribution has a little effect on the vertical compression strain on the subgrade top except for the convex half sine wave non-uniform distribution. And the maximum tensile strain at the bottom along the driving direction is larger than that along the tyre width regardless of the wheel loading distribution. In addition, the damage for the flexible base asphalt pavement structure is permanent deformation, specifically the allowable number of load repetitions to limit rutting for convex half sine wave non-uniform distribution is the smallest among all the computational cases.