Tire Footprint Research Articles

Evaluation of the Changes in Dimensions of the Footprint of Agricultural Tires under Various Exploitation Conditions

This paper presents an innovative method to determine the impact of agricultural wheels on soil. The experiment was conducted under controlled conditions, and the parameters of the tire footprints on the soil were analyzed. The tested parameters were the width, length, and depth of the footprint, the cross-section area of the tire, and the area of the footprint. All parameters were determined using the 3D scanning method. Two types of tires, two levels of vertical load, and three levels of inflation pressure were used. The aim of the research was to demonstrate differences in changes in the footprint parameters as a result of changes in the operational parameters of the tires. It was found the bias-ply tire was less responsive to changes in the width and length of the footprint than the radial tire. Moreover, it was shown that radial and bias-ply tires achieved similar values for the footprint area but in the case of bias-ply tires, there was a much greater footprint depth. This means that the side parts of the footprint of bias-ply tires have a more vertical profile, so they carry the vertical loads to a lesser extent.

ХАРАКТЕРИСТИКИ ПОВЕРХНІ ПОКРИТТЯ ДОРОЖНЬОГО ОДЯГУ СТАНДАРТНІ МЕТОДИ ВИМІРЮВАННЯ

Abstract. The texture of a road pavement surface and its skid resistance which concerns its ability to resist the vehicle wheel skidding have been accepted worldwide as the road safety criterion. These characteristics are interconnected in that the texture affects the skid resistance. The goal of the paper is to carry out the comparative analysis of valid road safety and performance parameters and its dependence on the road pavement surface texture and the comparative analysis of international and regional standard methods of road surface texture and skid resistance measurements covering methods acceptable for the road network survey. The main principles of the road pavement surface texture categorization were analyzed with its ranging as micro-, macro- and megatexture where the microtexture parameters sufficiently influence adhesion between pavement and tire especially in wet conditions. It was stated also that the macro- and megatexture parameters govern the rolling resistance and dynamic effect where the last is attributable to the comparable dimensions of the megatexture wavelength and the tire footprint and also affects the increase in loading that may be equal to the additive ESALs up to 40 %. The high-range wavelength roughness exceeding λ = 500 mm should be viewed as the road surface unevenness, as the feature negatively governing the vehicle road-holding ability. Also the contemporary high-performance techniques and methods for the road pavement surface skid resistance determination were reviewed and it was shown that these method and the according equipment should be divided as performing the longitudinal friction measurements or the side-way force measurements to be carried out under conditions that allow the investigators to distinguish the contribution made by the road pavement surface characteristics to the friction force. The possibilities of the usage of the results of the mathematical analysis of the road surface profile survey were analyzed separately and it was shown that the power spectral density can be accepted as a valid parameter for non-direct estimation of the road surface texture through international roughness index IRI. Keywords: road pavement, surface texture, profilometer, skid resistance, slid angle, friction coefficient, international roughness index.

Comprehensive Grounding Performance Evaluation of Tires Based on the Analytic Hierarchy Process

ABSTRACT The contact patch between tire and road surface has a direct impact on tire grounding performance. Acquiring tire grounding performance either by testing or simulation is not only time intensive but comes at a high cost. This paper proposes an effective means of evaluating tire grounding performance based on the tire-ground contact pressure distribution. This paper adopts fifteen characteristics to describe the tire-ground contact patch in which twelve structural schemes were designed for a certain type of tire. By using the simulation test method, the grounding performance characteristics such as grip performance, rolling resistance, wear performance, and the tire footprint characteristics were obtained. Correlation analysis was used to explore the relationship between tire grounding performance and footprint characteristics. Based on the correlation analysis and expert judgement, the analytic hierarchy process (AHP) model for comprehensive grounding performance evaluation of a tire was constructed. Then judgment matrix of the AHP model was established, and the consistency or otherwise of the judgment matrix was verified. The model was then used to evaluate and predict the four design schemes of tires. The evaluation results were in good agreement with the simulation test results, which shows that the construction method of the tire comprehensive grounding performance evaluation system proposed in this paper is practical. It is also evident that grounding performance evaluation of a tire based on the tire footprint is feasible.

Evaluation of Tires Acting on Soil in Field Conditions Using the 3D Scanning Method

This research presents the results of tests conducted under field conditions and included measuring the footprint of tires on soil. Two agricultural tires of the same size but different internal structures were tested, 500/50R17 (radial) and 500/50-17 (bias-ply). The factors were tire inflation pressure (0.8 bar, 1.6 bar, and 2.4 bar) and tire vertical load (7.8 kN, 11.8 kN, and 15.7 kN). The footprint made on the soil was scanned with a 3D scanner, resulting in a digital image of the tire footprint on the soil to enable an analysis of the measured parameters: length, width, depth, and contact area (in 3D form). Statistical analysis showed that for radial tire footprints, both inflation pressure and vertical load had a significant effect on all analyzed parameters. For bias-ply tire footprints, it was shown that only inflation pressure had a significant effect on all of the analyzed parameters, while the significance of the effect of the vertical load was not confirmed for the footprint depth. Based on the results obtained, the suitability of models describing the relationship between operating factors and the actual footprint area was verified. It was found that for a radial tire, the model formulated based on laboratory tests can predict the contact surface under field conditions (the correlation coefficient R2 was equal to 0.9226). In the case of a bias-ply tire, the correlation coefficient R2 reached a value equal to 0.5828. This indicates a less accurate estimation of the surface area under field conditions based on the model designed after laboratory testing.

Evaluation of Tire Footprint in Soil Using an Innovative 3D Scanning Method

This paper presents the results of the measurement of tire footprints in soil. The research was conducted under laboratory conditions using soil-filled cases. The research objects were two tires: a radial tire and a bias-ply tire of the same size. The variable parameters were vertical load (7.8 kN, 15.7 kN, 23.5 kN) and inflation pressure (0.8 bar, 1.6 bar, 2.4 bar). Test benches with a mounted tire, a soil case, and a 3D scanner were used in the research. Using the test bench, a tire was loaded with each inflation pressure, and a tire footprint was generated in the soil. Then, a 3D scanner was used to scan the tire footprint, and the parameters of length, width, depth, and tire–soil contact area (as a spatial image) were evaluated using special software. Then, mathematical models were formulated (separately for each type of tire) to describe the tire–soil contact area of the tire footprint as a function of the vertical load and inflation pressure. It was found that the depth of the tire footprint is an important parameter that influences the tire–soil contact area value. However, it was also found that with the right combination of inflation pressure and vertical load, a longer and wider, but shallower, tire footprint can be generated, the contact area value of which is similar to that of a deeper footprint.

Multiscale modelling and simulation for asphalt pavements under moving tire footprint loads

ABSTRACT The tire-pavement interaction has become an important research topic in recent years as the road transportation system and automobile industry develop. The distribution of contact stress between tires and asphalt pavement caused by traffic load is nonuniform. Furthermore, the asphalt mixture is a typical heterogeneous composite material, consisting at the microscale of aggregates, asphalt binder and air voids. However, much of the previous research has tended to focus on uniform-loaded pavement structure, which is comprised of homogeneous asphalt mixture. In this study, the inhomogeneous contact stress was applied on the macroscale finite element pavement model to study the influence of footprint on the mechanical properties of the asphalt pavement. The effect of tire contact stress on asphalt mixtures was investigated using a coupling method between the pavement model and a microscale model of asphalt mixture. This proposed algorithm is capable of simulating the impact of traffic load on the pavement structure and the asphalt mixture in real situations. It is useful for gaining a better understanding of the deformation processes that occur within the asphalt mixture under the real traffic load, which cannot be derived from the conventional laboratory tests and thus is beneficial to the pavement design.

Relationship between the 3D Footprint of an Agricultural Tire and Drawbar Pull Using an Artificial Neural Network

HighlightsImprovement of tractor traction provides better field efficiency.Drawbar pull increased with tire footprint length.Drawbar pull decreased with increasing tire footprint volume and depth.3D footprint parameters, which the 2D footprint do not contain, affected the drawbar pull significantly.The ANN highlighted the relation adequately.Abstract.Improving the traction of an agricultural tractor on the field increases its working efficiency and capacity. Heavy work, like plowing, entails high levels of tire slip, which is directly related to power loss when the transmission of drawbar pull is required. Accordingly, it is possible to hypothesize that a tire with a higher traction capability could increase the working efficiency of the machine. The natural evolution for measuring the geometrical parameters of tires has led to the consideration of three-dimensional (3D) footprints since the distribution of the vertical stresses at the soil–tire interface may be highly non-uniform. In this study, the data acquired from 3D footprints of 10 sets of tires underwent processing along with the data from drawbar tests carried out with the same tires on soil terrain at different slip ratios. Subsequently, artificial intelligence multivariate methods based on artificial neural networks allowed traction prediction and verified the importance that the acquired geometrical parameters have on the measured drawbar pull. The study confirmed the correlation of the geometrical parameters of the 3D tire footprint with the drawbar pull and the results of the artificial intelligence modelling underlined the impact of these acquisitions. However, further work that considers various lug geometries is required to extend the generalizability of the studied methodology. Keywords: Field efficiency, Phenolic resin, Traction, Tractor.

Investigation of flexible pavement maintenance patching factors using a finite element model

Patching of flexible pavements is one of the most important functions of pavement maintenance. Although finite element modeling has become commonplace in the world of pavement engineering, modeling has not yet been significantly leveraged for maintenance applications which improve safety, ride quality, and pavement service life. The objective of this study was to model viscoelastic properties of pavement and patching materials to determine the effect of various repair factors on pavement performance using the finite element method. Specifically, surface permanent deformation, local shear stress concentration, and horizontal strain distribution were investigated. Two types of models were simulated; the first model applied static loading to a surface layer fixed on a plate and the second model applied cyclic traffic loading to a two-layered flexible pavement system. The results demonstrate the importance of patching using a semi-permanent method. The results also demonstrated the accumulated effect of repeated loading using a time-dependent material response. Results also indicated that a larger patching area resulted in less influence of the shape of the area, while a circular area proved superior to a conventional rectangular patch for sizes near the tire footprint and smaller than it. Different responses were observed depending on the type of patching material modeled, demonstrating the effect of material choice in maintenance applications. Finally, mesh optimization was performed to ensure appropriate mesh sizes are used in future studies to accurately represent the pavement layers and patches.

Research and modeling of tire cornering characteristics considering tread wear based on UniTire model

In view of the complexity of tire structure and working conditions, tire models are often based on complete and accurate test data. In combined with the theory of tire dynamics, the empirical and semi-empirical tire models are built. In order to accurately measure the tire mechanical properties, it is necessary to strictly control the wear state of the tire tread during the tire test. But there is still a certain amount of wear, which does not guarantee the consistency of the data. In order to study the influence of wear on the mechanical properties of the tire, based on the tire footprint pressure distribution model and brush model theory, combined with the brush model theory and the rubber block shear stiffness deformation theory, the tire cornering stiffness model under different wear conditions is established. The footprint pressure distribution model is built based on the results of footprint test under different wear conditions. And combined the test result with different tread wear conditions and the theory of brush model, the tire brush model considering tread wear conditions is built. Based on the above theoretical model, the UniTire tire cornering slip model considering the tread wear state is established. To verify the accuracy of the model, the UniTire cornering slip model is obtained by using the cornering slip data in three tread wear states, and the tire mechanical properties of the other tread wear conditions are predicted. The error between the simulation results of the model and the experimental results is small, which effectively prove the predictive ability of UniTire cornering slip model considering tread wear. This study will help to improve the UniTire tire model and provide theoretical and technical support for the UniTire indoor and outdoor expansion applications.

Transient abrasion on a rubber sample due to highly dynamic contact conditions

Abrasive processes, primarily the local slip, are the dominant contributor to friction and wear of vehicle tires in service. The time history of forces accompanying acceleration, braking, and cornering in particular, lead constantly to changing contact conditions under the tire. Consequently, a laboratory test taking into account not only surface texture but also tire contact times (in the range of milliseconds) as well as realistic contact forces in a freely controllable temporal sequence is desirable. This paper presents the study of the dynamic contact between a rubber block and the abrasive surface at conditions close to those in a tire footprint. In our case, the test samples are a miniaturized tread block allowing to reproduce the intermittent tire contact including correct contact timings, pressure and friction coefficients in dependence on the driving maneuver to be tested. An analysis and comparison of friction and wear mechanisms for continuous contact and defined contact times is presented surpassing the characterization capabilities of DIN abrasion testers.Two different compounds with a variation of stiffness are examined. The grip and wear rates are analyzed and compared. It is shown that understanding the dominant mechanisms and quantifying tire tread friction and wear in detail require the consideration of realistic transient dynamics of a tire tread block impacting the road at each revolution of the tire.

Cumulated frictional dissipated energy and pavement skid deterioration: Evaluation and correlation

Pavement skid resistance, affecting wet-road accidents, deteriorates over time because of material properties, laying conditions, weather/seasonal effects and traffic. Skid resistance deterioration models are critical for design, maintenance and rehabilitation purposes, but very few of them explored the influence of traffic in terms of vehicle type and travel mode.This paper shows how it is possible to better model skid resistance deterioration by evaluating cumulated frictional dissipated energy in the tire footprint area. Full-scale accelerated pavement wear tests have been performed and analysed through an energy-based approach. Preliminary results seem promising for redefining the effect of traffic in deterioration models.

An Experimental–Numerical Approach for Modelling the Mechanical Behaviour of a Pneumatic Tyre for Agricultural Machines

The mechanical behaviour of an agricultural tyre is a matter of extreme interest as it is related to the comfort of operators, to the adherence of agricultural machines, and to the compaction of agricultural soil. Moreover, the deformability of the tyres plays a fundamental role in vehicle stability in terms of side rollover. The behaviour of a loaded tyre during its deformation is complex, due to the combined contributions of the carcass components, the tread rubber and the air contained within it. Therefore, this study proposes an experimental–numerical approach for the mechanical characterization of agricultural tyres based on real-scale experiments and matches these results with a finite-element (FE) model. The tyre flattening in the elastic field has been described using two coefficients (Young’s modulus “E”, Poisson’s ratio “ν”), whose values have been identified with an iterative FEM procedure. The proposed approach was applied to two different tyres (420/85 R24 and 460/85 R34), each one inflated at two different pressures (1.0 bar and 1.6 bar). Young’s modulus was appreciated to be highly variable with the inflation pressure “p” of the tyres. Furthermore, the response surface methodology was applied to find two mathematical regression models, useful for studying the variations of the tyre footprint dimensions according to the type of tyre. This simple approach can be applied in other simulations without suffering any loss of accuracy in the description of the phenomenon.

Longitudinal hydroplaning performance of passenger car tires

ABSTRACT It is universally agreed that tire hydroplaning has a significant impact on road safety. The occurrence of this phenomenon makes it difficult to appropriately manage accelerating, braking or steering, due to a considerable reduction of wheel forces. In this research project, the longitudinal hydroplaning test was conducted, according to the common VDA test procedure under acceleration. Results are presented, which quantify test parameters during the measurement, such as vehicle velocity, gate distance and longitudinal tire slip ratio. The article further identifies the impact of test conditions (wheel normal load, tire inflation pressure and water depth) on the longitudinal hydroplaning performance. In addition, the respective dynamic tire footprint characteristics are determined and linked to the performance. In the course of the analysis, it is shown that the empirical equation, developed by Horne to predict the critical hydroplaning velocity of truck tires, can be applied to passenger car tires. These results contribute to enabling a better understanding of how footprint characteristics affect longitudinal hydroplaning performance under acceleration conditions.

Objective Tire Footprint Segmentation Assessment from High-Speed Videos

ABSTRACT The tire establishes the contact between the vehicle and the road. It transmits all forces and moments to the road via its contact patch or footprint and vice versa. The visual inspection of this contact patch using modern optical equipment and image processing techniques is essential for evaluating tire performance. Quantitative image-based analysis can be useful for accurate determination of tire footprint under various operating conditions. Very frequently, methods used in tire footprint segmentation cannot be assessed quantitatively due to the lack of a reference contact area to which the different algorithms could be compared. In this work, we present a novel methodology to characterize the dynamic tire footprint and evaluate the quality of its segmentation from various video sequences in the absence of a ground truth.

Study on improvement of LuGre dynamical model and its application in vehicle handling dynamics

The accurate description of contact characteristics between tire and road surface may significantly affect the vehicle motion simulation and control analysis. Based on the LuGre tire model, the pressure distribution function of loading is modified as a non-uniform distribution pattern through new method of recursion formula. The mathematical expression of modified LuGre tire model is achieved through introducing the Bouc-Wen model to reflect tire hysteresis behavior, which takes into consideration the process of dynamic effect of tire vertical loading and tire footprint length. The effectiveness of model is verified through comparison with classic magic formula (MF) and LuGre tire model. Furthermore, the stability of solution for the modified LuGre tire model in the prediction of tire force and alignment torque is demonstrated in frequency domain. Finally, a nonlinear four-DOF vehicle handling dynamics model is built. The front wheel steering angle and the rotational angular velocities of the six tire from a calibrated virtual vehicle is entered into the vehicle model system with modified LuGre tire model as input data. The responses of longitudinal velocity, lateral velocity, yaw rate and roll angle are obtained under two kinds of limit conditions. The comparison results demonstrate the correctness and effectiveness of the built model, which further prove that the modified LuGre tire model is applicable for handling performance analysis of vehicle system.

Estimation of the Dynamic Contact Area From a Rolling Tire Correlated to Expert Assessment

Characteristics of the tire footprint are major indicators of tire performance and provide relevant information that can be used to improve the tire design process. However, the accurate segmentation of the tire footprint requires prior training and can be a highly man-hour consuming task. In order to overcome such drawbacks, scientists have made multiple efforts to design methods for segmenting the tire footprint automatically but it is still an open problem. In this paper, we propose a novel methodology to estimate the tire footprint under dynamic conditions and conduct an extensive subjective assessment of its quality. For this aim, we designed a subjective evaluation procedure based on the ITU-R BT.500–13 recommendation. In addition, we include a quantitative comparison of several tire contact patch segmentation methods using ray feature error and Dice index. The results of our methodology have been evaluated by expert tire engineers and will allow us to improve the tire manufacturing process.

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.

Dynamic simulation analysis of the tire-pavement system considering temperature fields

In order to analyze tire footprints in different conditions and calculate dynamic responses of asphalt pavement with vehicle braking, a tire-pavement coupling simulation system, which can use a viscoelastic constitutive model of asphalt concrete considering temperature dependence, is established. The user subroutine of the material model was programmed by the FORTRAN language, and viscoelastic parameters of the material model were recognized based on dynamic strain data of dynamic impact tests, whose validity was verified by using test data in the literature. The tire-pavement coupling simulation system was established to analyze tire footprints in static and dynamic conditions at different temperatures of asphalt concrete layer, whose calculation accuracy of the numerical simulation was verified. Based on measured temperature data at different depths of an actual pavement structure and the corresponding simulation model, thermal parameters of each layer in the pavement structure were recognized. Field distributions of the viscoelastic parameters in the asphalt concrete layer of the coupling simulation system were obtained by using the heat transfer analysis and the user subroutine. Average braking decelerations of trucks at a chosen intersection were calculated according to the investigation data. Based on the tire-pavement coupling simulation system, peak values of dynamic shear strain in the asphalt concrete layer at the intersection were calculated, which considered the coupling effect between axle loads and temperature fields.

3D brush model to predict longitudinal tyre characteristics

ABSTRACTA 3D tyre brush model, which aims to predict the longitudinal tyre characteristic under steady-state conditions by modelling the occurring physical effects in the tyre–road contact patch, is presented. The model includes an analytical method to describe the tyre footprint geometry, the pressure distribution, the slip due to the lateral tyre contour, the slip due to braking or traction and the longitudinal as well as the lateral shear stresses on a flattened tyre. The presented development tool offers a method to investigate different rubber friction data (caused by different tread compounds and/or surface textures) and to analyse its influence on longitudinal tyre characteristics. The tyre design is fixed (same casing, dimension and pattern). The results include the shear stresses as well as the different sliding velocities in the contact patch for different slip conditions. The model was developed for a standard summer pattern design and a standard tyre dimension (205/55R16). It can also be adapted to other tread designs and tyre dimensions. To offer a good comparability between model results and test bench measurements, the surface curvature of an internal test rig is considered.

Grip Analysis of Road Surface and Tire Footprint Using FEM

Road grip involve a touch between road pavement and the tire tread pattern. The load bearing surface, which depends on pavement roughness and local pressures in the contact patch. This research conducted to develop a Finite element model for simulating the experimentally testing of asphalt in Jl. AH Nasution Medan, North Sumatera Indonesia base on the value of grip coefficient from various tire loads and the various speed of the vehicle during contact to the road. A tire model and road pavement are developed for the analyses the geometry of tire footprint. The results showed that the greater the mass of car will increase grip coefficient. The coefficient of grip on the road surface contact trough the tire footprint strongly influence the kinetic coefficient of friction at certain speeds. Experimentally show that Concrete road grip coefficient of more than 34% compared to the asphalt road at the same IRI parameters (6-8). Kinetic friction coefficient more than 0.33 was obtained in a asphalt path at a speed of 30-40 Km/hour.