Tire-pavement Contact Stresses Research Articles

Study on the influence of belt angle on tire grounding characteristics under longitudinal slip conditions

Using ABAQUS software as a tool and 225/60R18 tire as the research object, a finite element model of the tire was established and longitudinal slip simulation was conducted based on the completion of longitudinal slip and rubber material tests. By comparing the tire-pavement contact stress under longitudinal slip conditions with different angles of belt layers and the stress on the first belt steel cord, the influence of different angles of belt layers on the grounding characteristics of tires were analyzed. The results showed that under static loading conditions, the trend of tire-pavement contact stress presented a symmetrical “W” shape. Under dynamic longitudinal slip conditions, the tire-pavement contact stress curve was significantly different from the static loading simulation, with significant fluctuation and presented an irregular “W” shape, and asymmetric distortion occurred with the change of slip rate. At higher slip rates (±20%), the higher the asymmetry of the grounding imprint at the 61° and 63° belt layer angles. At the 65° belt layer angle, the ground imprint is more evenly distributed on the tread. The curve of stress variation on the belt steel cord along the path is in an “M” shape, and the stress on the belt steel cord is mainly distributed symmetrically on the tire-pavement contact surface corresponding to the tire shoulder position. The higher the slip rate, the higher the asymmetry of the stress distribution on both sides of the belt steel cord. At 65° and 67° belt angles, the distribution of grounding imprints on the tread are more uniform, and the tread is less prone to deformation, resulting in lower tread wear.

Numerical investigation on viscoelastic response of asphalt mixture under tire braking slip

A three-dimensional (3D) viscoelastic asphalt pavement, of which the surface was composed of asphalt mixture, was developed using ABAQUS and a moving 3D tire-pavement contact stress with different braking slip ratios was incorporated and programmed into ABAQUS by FORTRAN language. Five braking slip ratios were considered (Dual Tire Assembly (DTA): 0 (free rolling), 1.8%, 3.6%, 5.4%, and 7.0% (full braking); Wide Base Tire (WBT): 0 (free rolling), 1.5%, 3.0%, 4.5%, and 7.0% (full braking)). Results showed that the viscoelastic stress and strain of the asphalt mixture were significantly influenced by tire braking slip ratio and pavement temperature for both DTA and WBT loading conditions. As the slip ratio and the temperature increased, the stress and strain of the asphalt layer would increase and their positions shifted upwards to the surface of the asphalt layer. Comparatively, the peak shear strain was the most significantly influenced factor and its amplitude may increase by 10 times. However, the bottom strain of the asphalt layer was far less affected by tire breaking behaviours.

Numerical simulation of mechanical response analysis of asphalt pavement under dynamic loads with non-uniform tire-pavement contact stresses

The selection of accurate input design parameters is important for understanding the dynamic response of an asphalt pavement structure. The transverse and longitudinal shear stresses that affect the dynamic response of asphalt pavement are not considered in traditional asphalt pavement design. To this end, this study utilizes the finite element method (FEM) to analyze the mechanical response of asphalt pavement under dynamic loads with non-uniform tire-pavement contact stresses. For this purpose, firstly a three-dimensional (3D) finite element (FE) model of a rubber tire is developed. Secondly, the predicted and laboratory measured stresses are compared to develop a 3D FE model of the contact stresses. Finally, a 3D FE model of the tire–pavement contact is analyzed to investigate the influence of shear stresses on the response of the asphalt pavement and the superposition effect of the mechanical response. The results show that the distribution and magnitude of the vertical contact pressure under the free-rolling state are the same as those under the static state, and the traction and braking conditions could change the symmetry of tire-pavement interactions. In addition, the shear stress at the tire-pavement interface affects the peak response of the surface layer, indicating that shear stress plays a considerable role in controlling the development of rutting and longitudinal cracks. Considering the viscoelasticity of the asphalt material, it is observed that the superposition effect of the mechanical response is a comprehensive result of the space–time domains. In conclusion, this study analyzes the influence of tire-pavement contact on the mechanical response of asphalt pavement and proposes input design parameters for improving the design of asphalt pavement.

ContactGAN development – prediction of tire-pavement contact stresses using a generative and transfer learning model

ABSTRACT An accurate characterisation of tire-pavement contact stresses is important for pavement structural analysis and performance evaluation. The demand for rapid pavement design and analysis requires a simple, accurate, and robust approach that pavement engineers can easily use. In this study, a generative adversarial network model – ContactGAN – was developed to replace the finite element analysis (FEA), for predicting the three-dimensional (3D) non-uniform contact stress. The ContactGAN model consists of a Generator that generates synthetic stress fields, and a Discriminator that distinguishes synthetic and FEA-generated stress fields. Three finite-element (FE) generated tire contact stress datasets were used. Compared with the previously developed ContactNet model, the ContactGAN model produces a more accurate contact stress distribution in both the overall quality and the most critical values. As part of the deep learning model, a transfer learning method was developed to address the challenges of applying the model to tasks with minimal datasets. After the transfer learning approach is applied, the mean square errors (MAEs) of the 3D contact stress predictions of the cornering tire dataset and the hyper-viscoelastic tire dataset are reduced by 83.8% and 92.9%, respectively. This research delivers a data-driven approach for the rapid and accurate prediction of tire-pavement contact stresses.

Integrated Vehicle–Tire–Pavement Approach for Determining Pavement Structure–Induced Rolling Resistance under Dynamic Loading

Pavement-related rolling resistances, caused by pavement–vehicle interaction, are important components of pavement life-cycle assessment (LCA). Structure-induced rolling resistance (SRR) is caused by dissipated vehicle kinetic energy in the pavement structure. This paper presents an integrated vehicle–tire–pavement approach to evaluate asphalt pavement SRR under dynamic loading. A three-dimensional (3D) semitrailer-truck model was used to calculate dynamic wheel loads on various pavement surface-roughness profiles. The dynamic wheel loads were then transformed into 3D tire–pavement contact stresses using a deep-learning tire model. Next, an advanced 3D finite element pavement model, validated in previous studies, was used to simulate pavement structure under moving tire–pavement contact stresses. The dynamic load coefficient of axle forces was found to increase linearly with truck speed. The increasing trend became more significant as pavement roughness increased. Ignoring the dynamic loading effect resulted in 12% error in predicting SRR. A case study was performed to illustrate the computation procedures of asphalt pavement SRR under static and dynamic loading. Dynamic loading accounted for 4.74%, 7.37%, 10.73%, and 14.02% of SRR for four pavement surface-roughness levels at a truck speed of 40 mph. In addition, SRR was found to be highly nonlinear and increased as speed decreased and axle load increased. A modified Illinois Center for Transportation SRR model was developed to quickly assess the SRR component of the pavement LCA’s use stage. This study demonstrates the importance of vehicle–tire–pavement interaction in SRR prediction, which may not be overlooked.

Rutting and surface-initiated cracking mechanisms of semi-flexible pavements with cement asphalt emulsion pastes

ABSTRACT The semi-flexible pavement (SFP) has been used as a promising wearing course in heavy traffic roads. It is crucial to investigate the main failure mechanisms caused by different influencing factors on SFPs at medium and high temperatures. In this research, utilising a three-dimensional (3D) finite-element model (FEM), the performance of SFP and conventional pavement under realistic tire–pavement contact stresses was compared by computing the critical responses associated with rutting and top-down cracking (TDC). Besides, experimental studies were conducted on typical asphalt concrete (AC16) and four types of SFP mixtures grouted with cement paste and cement asphalt emulsion pastes (CAEPs) to evaluate their rutting resistance and fatigue cracking potential at medium and high temperatures. The numerical analysis results indicated that SFP mixtures with lower asphalt emulsion (AE) content enhanced rutting resistance significantly while TDC potential was reduced at higher percentages of AE. Compared to dual-tire assembly, the wide-base tire led to less TDC damage and asphalt layer (primary) rutting, but more subgrade (secondary) rutting once carrying the same load. Moreover, based on the findings of laboratory evaluation, SFP with CAEP presented the best performance in terms of fatigue life and permanent deformation when AE to cement by weight (AE/C) was no more than 0.4.

Three-dimensional tire-pavement contact stresses prediction by deep learning approach

ABSTRACT The demand for fast and accurate tire-pavement contact modelling is becoming increasingly prevalent with the advancement of pavement design and finite-element modelling. This paper presents a tool for fast and accurate prediction of non-uniform tire-pavement contact stresses utilising deep learning. Two truck tires, under various wheel loading, inflation pressure, and slip ratio conditions, were considered. The developed deep learning model, ContactNet, is a deconvolutional neural network consisting of two fully connected layers, one reshape layer, and five deconvolution layers with millions of neurons. Two validated finite-element truck tire models were used to generate a contact stresses database with 1800 simulated results. The database was then used for training and testing of the ContactNet. The ContactNet resulted in average errors of 0.80%, 0.77%, 0.90%, and 0.57% in predicting maximum vertical stress, effective contact area, maximum longitudinal stress, and maximum transverse stress. The mean absolute error of the ContactNet prediction is 0.91 kPa. This significantly outperformed four conventional machine-learning regression methods investigated in this study, including polynomial regression, k-nearest neighbours, multi-layer perceptron, and random forests.

Effect of the tire – Pavement contact at the surface layer when the tire is tilted in bend

Tire-pavement interaction is a rolling contact problem that depends on tire and pavement factors, such as vehicle speed and weight, material and type of tire, tire pressure inflation, camber and texture of the surface layer. In this paper, the problem of tire-pavement contact is studied using a realistic description in normal section and bend. The study focuses on the shape of the contact patch and the stress distribution at the tire-pavement interface and the surface shear stresses rather than internal stresses in the structure of the pavement. The numerical approach introduced requires precise tire geometry (estimated by a photogrammetry method) and an equivalent Young's modulus (function of the inflation pressure resulting from the press load tests). Vertical contact stress at the tire-pavement interface predicted by a Semi-Analytical model were compared to experimental measurements with a press system under different loads and angles of inclination. Finally, we discuss the effect of the tire inclination on the calculated shear stresses (origins of damage in turns). The model shows that the increase of the angle of inclination in a turn has a direct influence on the distribution of the tire-pavement contact stresses and the shear stresses. These results will provide indications for the evaluation of the performance of the surface layer with respect to rutting and downward cracking.

Three-dimensional finite element analysis of top-down crack propagation in asphalt pavements

In this study, the mechanisms of top-down crack (TDC) propagation were investigated based on viscoelastic finite element (FE) analyses. By computing J-integral through 3D FE viscoelastic analyses, TDC propagation mechanisms were examined in pavement structures with cement-treated base (CTB) and granular base (GB) and different asphalt concrete (AC) layer thicknesses. The results showed that applying realistic tire-pavement contact stresses caused TDCs propagation rate to increase 1.15 to 5.45 times due to mixed-mode I + II fracture. However, the proportion of tensile and shear modes was significantly affected by the TDC depths. In addition, by increasing temperature from 25 to 50 °C, J-integral increased 3.5 to 4.4 times at different depths. Due to vehicle speeds reduction from 96 to 8 km/h and viscoelastic impact at lower speeds, TDCs propagation rate increased up to 1.9 times in different depths analyzed.

Analysis of the Tire-Pavement Contact Stress Characteristics during Vehicle Maneuvering

The vehicle maneuvering condition plays an important role in the analysis of the contact stress characteristics of the tire-pavement interaction. A reliable three-dimensional (3D) tire-pavement interaction model was developed to simulate the interface contact stress at static and various rolling conditions (free rolling, acceleration and braking). First, the 205-55-R16 radial tire was modeled accurately comprised of its special pattern and materials in the finite element software ABAQUS. Next, we analyzed and compared these contact stress characteristics, including the distribution of contact stress, the peak contact stress and the variation of stress with time at free rolling, acceleration and braking conditions. Results showed that under the same vehicle load and inflation pressure, the tire-pavement contact stresses at free rolling condition are always much larger than those at static loading condition. At acceleration condition, the peak contact stress occurs at the inner edge of the tire outermost ribs. At deceleration condition, the stress concentration on the tire tread is weakened with the extension of time. The peak contact stress increases with time at acceleration and braking conditions. But the peak contact stress at braking is much larger than that at acceleration condition under the same load and inflation pressure.

A review of top-down cracking in asphalt pavements: Causes, models, experimental tools and future challenges

Abstract In the last decades, a new type of distress has been observed more and more frequently on asphalt pavements. This distress, ascribable to fatigue failure, has been named top-down cracking (TDC) because it consists in longitudinal cracks that initiate on the pavement surface and then propagate downwards. A series of surveys recently carried out on Italian motorways highlighted that TDC can affect up to 20%–30% of the slow traffic lane. Therefore, in order to achieve a better understanding of such distress, this paper reviews causes, models and experimental tools and highlights future challenges for TDC. The literature review indicates that TDC can evolve on the pavement surface in three stages (i.e., single crack, sister cracks, alligator cracking) and, below a certain depth, the cracks can form angles of 20°–40° with respect to the vertical plane. Even though multiple factors contribute to TDC development, thick pavements are more likely to fail due to TDC induced by tire-pavement contact stresses, especially in the presence of open-graded friction courses (OGFCs). Moreover, in literature there are several TDC models based on mechanics (e.g., fracture mechanics or continuum damage mechanics) which allow a rigorous study of crack initiation and propagation. Future challenges include the identification of a reliable and feasible test method, among those proposed in literature, to study the TDC performance of asphalt mixtures and the implementation of TDC in pavement management systems (PMSs) through the definition of criteria for TDC recognition in the field as well as for the rehabilitation depth evaluation. Finally, more research is needed for open-graded asphalt mixtures, which present critical drawbacks in terms of TDC.

Tire-Pavement Contact Stress Characteristics and Critical Slip Ratio at Multiple Working Conditions

The contact stress distribution of tire-pavement is generally assumed to be uniformly distributed in circles or rectangles in the pavement design. This simplification can solve some common engineering problems, but it neglects two factors including magnitude and direction of the contact stress. The main purpose of this paper is to analyze the contact stress distribution between the bus tire and the pavement under different driving conditions and pinpoint and compare the critical slip ratio during braking and acceleration. First, a tire-pavement simulated contact model is constructed by ABAQUS. Next, we compare, respectively, contact stresses in the vertical, longitudinal, and transverse directions at various rolling conditions and analyze the longitudinal forces at different slip ratios during braking and acceleration. It is observed that the magnitude, direction, and nonuniform distribution of contact stress are affected by the multiple working conditions while the bus is working. Meanwhile, in the braking and acceleration conditions, the longitudinal force grows rapidly as the slip ratio increases, and then grows slowly and at last decreases when the critical slip ratio is reached. However, the critical slip ratio at the time of braking differs from that at the time of acceleration, and the former is smaller than the latter.

Tire-Pavement System Modelling and Triaxial Contact Stress Analysis

In the pavement design, the tire load is usually assumed to be a circular or rectangular evenly distributed load, which is actually not like this. In order to provide data reference for the development of tire-pavement contact stress intelligent test instrument, it is necessary to model the tire-pavement system, and construct tire-pavement 3D finite element model using large finite element software. Firstly, establish three-dimensional model of tire and road surface, and impose certain loads and constraints. Secondly, the triaxial contact stress of the tire-pavement under static conditions is analyzed. Then the triaxial stress under traction conditions is analyzed, and the triaxial stress under different conditions of use of the tire is compared and analyzed. The results show that as the load of the tire gradually increases, the maximum vertical contact stress and the maximum longitudinal stress gradually decrease, but the maximum lateral pressure gradually increases. When the inflation pressure of the tire is gradually increased, the contact stresses in the three directions are correspondingly increased. However, the maximum vertical contact stress and maximum longitudinal stress increase more obviously than the maximum transverse contact stress. In addition, the transverse contact stress could be ignored under traction conditions.

Turning Maneuver Effect on Near-Surface Airfield Pavement Responses

Airport pavement structures experience heavy aircraft tire loading through a localized contact area. Distributed three-dimensionally and non-uniformly, tire-pavement contact stresses directly influence the near-surface behavior of flexible airfield pavements. The resulting high shear stress levels induced by aircraft tire loading may lead to instability through shoving or slippage cracking. As the tire turns during taxiing, the risk of near-surface damage is exacerbated. In this study, numerical modeling of an inverted pavement system and a conventional flexible pavement structure loaded with a single tire from the A-380 landing gear was developed. The analysis matrix included two tire-inflation pressures, two speeds, and rolling conditions that varied from free-rolling to two turning maneuvers. Two analysis approaches were performed: 1) use of traditional critical point strains, and 2) domain analysis, which characterizes bulk pavement behavior using multiaxial stresses and strains. The critical strains, which are used as inputs for airfield pavement design, changed negligibly under varying tire turning conditions despite the asymmetric contact stress distribution. On the other hand, domain analysis not only captured the asymmetric pavement behavior, but also identified that altering the tire movement from a free-rolling condition to turning could induce a significant increase in the potential damage.

Development of Domain Analysis to Predict Multi-Axial Flexible Airfield Pavement Responses Due to Gear and Environmental Loadings

Flexible pavement design procedures use maximum mechanistic strains to predict service life via empirical transfer functions. The conventional method of using predefined point locations for potential damage may not accurately represent realistic pavement scenarios. For instance, flexible airfield pavement analysis mainly considers the critical strain at the bottom of the asphalt concrete (AC), which may not characterize near-surface cracking potential. In lieu of point strains, domain analysis, a new method, accounts for the multi-axial behavior of pavements, as inherently excited by three-dimensional (3-D) and nonuniform aircraft tire–pavement contact stresses. Initially applied on highway pavements considering truck tire loading, this approach is an initial breakthrough for implementing domain analysis on flexible airfield pavements; in this study, A-380 and F-16 landing gear tire loads were considered. As anticipated, speed and temperature had significant influence on cumulative domain stress and strain ratios. The decrease in speed and increase in temperature not only increased the cumulative ratios up to 1.81, but nonlinearity of the problem became more prevalent at worst loading conditions (8 kph and 45°C). Minimal difference in ratios for F-16 cases suggests that the National Airport Pavement Test Facility pavement structure became less sensitive to conditions under low loads. Point response analysis revealed that critical strains were not significantly influenced by the tire-inflation pressure, for example, tensile strain at the bottom of the AC only increased up to 13.6% (considering 8 kph speed), whereas domain analysis quantified the increase with respect to 3-D stress or strain states.

Comparative Study of Asphalt Pavement Responses under FWD and Moving Vehicular Loading

AbstractThis study aimed to compare pavement responses caused by impulsive dynamic loading and moving vehicular loading using mechanistic pavement analysis. Finite-element (FE) models were developed to simulate falling weight deflectometer (FWD) loading with axisymmetric FE models and to simulate moving vehicular loading with three-dimensional (3D) FE models. Two flexible pavement structures with different asphalt layer thicknesses and temperature profiles were considered in the analysis. The FE models simulated dynamic impulse loading during FWD testing and moving tire loading patterns with 3D tire-pavement contact stresses. It was found that the pulse durations of compressive stresses in the asphalt layer were significantly affected by speed and pavement depth in what can be described as an exponential relationship. However, pulse duration was found to be pavement-dependent, and the quantitative relationship between pulse duration and speed and depth could only be developed for each individual pavement ...

Tire–Pavement Contact Stress with 3D Finite-Element Model—Part 1: Semi-Steel Radial Tires on Light Vehicles

Abstract Vehicles pass their loads through tires onto pavements. Traditionally, the vertical contact pressure is assumed to uniformly distribute in a rectangle or circular area, whereas the shear contact pressure is ignored in pavement design. Experiments have demonstrated that the interaction between the tire and the pavement surface is very complicated. The contact area is not a regular shape and the distribution of contact pressure is not uniform. However, experimental approaches to measure contact pressure are usually time and energy consuming, whereas the results are subject to errors introduced by measurement sensors. On the other hand, numerical simulation can describe the interaction between tire and pavement surface under all circumstances, such as various driving conditions, different tread types, and so on. In this paper, a three-dimensional finite-element model for tires was developed. The model was validated by the static test data. Then the interactions of different tires with pavement were analyzed, including the vertical and shear contact-pressure distributions on tires and on pavement surfaces. The influences of pavement friction and load level on the contact-pressure distributions of tires and pavement were investigated as well. It was found that vertical and shear contact pressures on tires and pavement were quite different when the type of tire or the friction changed. The contact-pressure distribution was found not uniform and the shape of contact area changed as the load level varied. The complicated interactions between different tires and pavement indicate that sophisticated tire models are necessary to obtain more accurate pavement responses.

Hyperelastic Modeling of Wide-Base Tire and Prediction of Its Contact Stresses

Description of tire model development using the finite element (FE) method is presented. Three-dimensional tire-pavement contact stresses were predicted for braking, traction, and free rolling using the FE method. Measured load-deflection curves, contact area, and contact stresses were used for model outcome validation. Slide-velocity-dependent friction and accurate input regarding geometry and material properties were considered. The developed tire model, which helped in studying contact stresses variation in each direction, was used to explain the various phenomena taking place at the tire-pavement interface during straight-line rolling. The analysis matrix includes nine rolling conditions and various loads, tire inflation pressures, and speeds. Vertical contact stresses were not significantly affected by speed or slip ratio; however, contact stresses were greatly modified along the in-plane directions by rolling conditions. Analytical expressions were introduced to represent vertical and longitudinal contact stresses for full braking and full traction. Formulas are presented for low speed and full braking, which are relevant for roadway intersections design.

Effect of Friction Model and Tire Maneuvering on Tire-Pavement Contact Stress

This paper aims to simulate the effects of different friction models on tire braking. A truck radial tire (295/80R22.5) was modeled and the model was validated with tire deflection. An exponential decay friction model that considers the effect of sliding velocity on friction coefficients was adopted for analyzing braking performance. The result shows that the exponential decay friction model used for evaluating braking ability meets design requirements of antilock braking system (ABS). The tire-pavement contact stress characteristics at various driving conditions (static, free rolling, braking, camber, and cornering) were analyzed. It is found that the change of driving conditions has direct influence on tire-pavement contact stress distribution. The results provide the guidance for tire braking performance evaluation.

Effect of Surface Friction on Tire–Pavement Contact Stresses during Vehicle Maneuvering

AbstractAccurate modeling of tire–pavement contact behavior plays an important role in the analysis of pavement performance and vehicle stability control. A three-dimensional (3D) tire–pavement interaction model was developed using the FEM to analyze the forces and contact stresses generated during vehicle maneuvering (free rolling, braking/acceleration, and cornering). A pneumatic radial-ply tire structure with rubber and reinforcement was simulated. The steady-state, tire-rolling process was simulated using an Arbitrary Lagrangian Eulerian (ALE) formulation. An improved friction model that considers the effect of sliding speed on friction coefficients was implemented to analyze the effects of pavement surface friction on contact stresses, friction forces, and cornering forces. The results showed that the magnitudes and nonuniformity of contact stresses are affected by vehicle-maneuvering conditions. As the pavement surface friction increases, the tangential tire–pavement contact stresses at various roll...