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S.K. Srirangam
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1
The surface texture of the pavement plays a very important role in driving the frictional properties at the tire rubber-pavement interface. Particularly, the hysteretic friction due to viscoelastic deformations of rubber depends mainly on the pavement surface texture. In the present paper, the effect of micromechanical pavement surface morphology on rubber block friction was brought in by comparing the friction results for three different asphalt mix morphological surfaces, named stone mastic asphalt (SMA), ultra-thin surfacing (UTS) and porous asphalt (PA). The asphalt surface morphologies of these mixes were captured by using an X-ray tomographer, from which the resulting images micromechanical finite element (FE) meshes for SMA, UTS and PA pavements were developed by means of the SimpleWare software. In the FE model, the rubber and asphalt binder were modeled as viscoelastic (VE) materials and the formulation was given in the large deformation framework. FE simulations were then carried out by using contact algorithm between rubber and the road surface. It was observed that the rubber friction inversely varies with the sliding speed and positively varies with the pressure for all the pavement morphological and stiffness conditions. Furthermore, it was observed that the highly porous pavement surface results in large dissipation of energy, hence, large rubber friction which shows that the mix characteristics of pavements have a significant effect on rubber friction.
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The surface texture of the pavement plays a very important role in driving the frictional properties at the tire rubber-pavement interface. Particularly, the hysteretic friction due to viscoelastic deformations of rubber depends mainly on the pavement surface texture. In the present paper, the effect of micromechanical pavement surface morphology on rubber block friction was brought in by comparing the friction results for three different asphalt mix morphological surfaces, named stone mastic asphalt (SMA), ultra-thin surfacing (UTS) and porous asphalt (PA). The asphalt surface morphologies of these mixes were captured by using an X-ray tomographer, from which the resulting images micromechanical finite element (FE) meshes for SMA, UTS and PA pavements were developed by means of the SimpleWare software. In the FE model, the rubber and asphalt binder were modeled as viscoelastic (VE) materials and the formulation was given in the large deformation framework. FE simulations were then carried out by using contact algorithm between rubber and the road surface. It was observed that the rubber friction inversely varies with the sliding speed and positively varies with the pressure for all the pavement morphological and stiffness conditions. Furthermore, it was observed that the highly porous pavement surface results in large dissipation of energy, hence, large rubber friction which shows that the mix characteristics of pavements have a significant effect on rubber friction.
Porous asphalt concrete (PAC) course is best known for its noise reduction and improved wet skid resistance characteristics. Nevertheless, the use of PAC is associated with reduced lifetimes and high maintenance costs, mainly owing to various distress mechanisms such as raveling. Therefore, it is necessary to have a better understanding of the stress states associated at the micromechanical level, that is, at the mastic-aggregate interfacial zone and the mastic itself. For this purpose, it is necessary to develop micromechanical finite element (FE) models that are composed of realistic asphalt mix meshes with different phases that are subjected to rolling wheel loads. A framework is presented to develop a three-dimensional FE model capable of simulating a rolling wide-base truck tire over an asphalt pavement surface. From results of FE simulations, the stress states at the mastic and mastic-aggregate interfacial layer were studied. For the analyzed surface of the PAC mix, it was observed that the mastic phase registered high stress states compared with the mastic-aggregate interfacial phase, suggesting that the sample may experience a cohesive failure in the long run. The developed methodology also provides a tool to analyze the influence of tire operating conditions such as tire inflation pressures and loads on the stress states of asphalt mixes. Finally, the micromechanical stress response of PAC mix was compared with that of other conventional asphalt mix designs, and it was found that the magnitude of stresses developed in the mastic of PAC are higher compared with the conventional asphalt mix designs.
...
Porous asphalt concrete (PAC) course is best known for its noise reduction and improved wet skid resistance characteristics. Nevertheless, the use of PAC is associated with reduced lifetimes and high maintenance costs, mainly owing to various distress mechanisms such as raveling. Therefore, it is necessary to have a better understanding of the stress states associated at the micromechanical level, that is, at the mastic-aggregate interfacial zone and the mastic itself. For this purpose, it is necessary to develop micromechanical finite element (FE) models that are composed of realistic asphalt mix meshes with different phases that are subjected to rolling wheel loads. A framework is presented to develop a three-dimensional FE model capable of simulating a rolling wide-base truck tire over an asphalt pavement surface. From results of FE simulations, the stress states at the mastic and mastic-aggregate interfacial layer were studied. For the analyzed surface of the PAC mix, it was observed that the mastic phase registered high stress states compared with the mastic-aggregate interfacial phase, suggesting that the sample may experience a cohesive failure in the long run. The developed methodology also provides a tool to analyze the influence of tire operating conditions such as tire inflation pressures and loads on the stress states of asphalt mixes. Finally, the micromechanical stress response of PAC mix was compared with that of other conventional asphalt mix designs, and it was found that the magnitude of stresses developed in the mastic of PAC are higher compared with the conventional asphalt mix designs.
Journal article
(2016)
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Santosh Srirangam, Kumar Anupam, D Casey, Xueyan Liu, Cor Kasbergen, Athanasios Scarpas
Road traffic is a major source of noise pollution. Road authorities and pavement researchers have been trying to reduce this noise pollution by laying quieter pavement surfaces. Poroelastic road surfaces (PERS) have been found to be the most effective solution because they are very porous and elastic in nature compared with conventional dense asphalt surfaces. However, the structural performance of PERS pavement under heavy traffic loads is still unknown. The aim of this study was to determine the critical stresses experienced by PERS pavement under heavy loads applied by a wide-base truck tire. For this purpose, finite element (FE) simulations of a wide-base truck tire rolling over a PERS pavement system were performed for various material properties of PERS and adhesive layers, speeds, tire loads, and inflation pressures. From the FE model results, the critical stress envelopes were constructed by using the concept of stress invariants. Stress invariants represent normal and shear stresses that might cause the PERS layer to fail under the critical combination of material, loading, and operating variables and therefore act as design indicators. The FE results showed that the higher contact pressures and the lower material stiffness resulted in higher stress invariants. It was also determined that the stiffness of the adhesive layer influenced the response of the PERS layer. The current study demonstrated a robust methodology for assessing the performance of a thin PERS layer pavement system under rolling–truck tire operating conditions.
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Road traffic is a major source of noise pollution. Road authorities and pavement researchers have been trying to reduce this noise pollution by laying quieter pavement surfaces. Poroelastic road surfaces (PERS) have been found to be the most effective solution because they are very porous and elastic in nature compared with conventional dense asphalt surfaces. However, the structural performance of PERS pavement under heavy traffic loads is still unknown. The aim of this study was to determine the critical stresses experienced by PERS pavement under heavy loads applied by a wide-base truck tire. For this purpose, finite element (FE) simulations of a wide-base truck tire rolling over a PERS pavement system were performed for various material properties of PERS and adhesive layers, speeds, tire loads, and inflation pressures. From the FE model results, the critical stress envelopes were constructed by using the concept of stress invariants. Stress invariants represent normal and shear stresses that might cause the PERS layer to fail under the critical combination of material, loading, and operating variables and therefore act as design indicators. The FE results showed that the higher contact pressures and the lower material stiffness resulted in higher stress invariants. It was also determined that the stiffness of the adhesive layer influenced the response of the PERS layer. The current study demonstrated a robust methodology for assessing the performance of a thin PERS layer pavement system under rolling–truck tire operating conditions.
The surface texture of the pavement plays a very important role in deriving the frictional properties at the tire rubber-pavement interface. Particularly, the hysteretic friction due to viscoelastic deformations of rubber depends mainly on the pavement surface texture. In the present paper, the effect of micromechanical pavement surface morphology on rubber block friction was brought in by comparing the friction results for three different asphalt mix morphological surfaces, namely, Stone Mastic Asphalt (SMA), Ultra-Thin Surfacing (UTS) and Porous Asphalt (PA). The asphalt surface morphologies of these mixes were captured by using an X-ray tomographer; from which the resulting images micromechanical finite element (FE) meshes for SMA, UTS and PA pavements were developed by means of the SimpleWare software (2011). These asphalt meshes were combined with the contact algorithm for the micromechanical analysis of the contact problem of rough surfaces.
...
The surface texture of the pavement plays a very important role in deriving the frictional properties at the tire rubber-pavement interface. Particularly, the hysteretic friction due to viscoelastic deformations of rubber depends mainly on the pavement surface texture. In the present paper, the effect of micromechanical pavement surface morphology on rubber block friction was brought in by comparing the friction results for three different asphalt mix morphological surfaces, namely, Stone Mastic Asphalt (SMA), Ultra-Thin Surfacing (UTS) and Porous Asphalt (PA). The asphalt surface morphologies of these mixes were captured by using an X-ray tomographer; from which the resulting images micromechanical finite element (FE) meshes for SMA, UTS and PA pavements were developed by means of the SimpleWare software (2011). These asphalt meshes were combined with the contact algorithm for the micromechanical analysis of the contact problem of rough surfaces.
Journal article
(2015)
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Santosh K. Srirangam, Kumar Anupam, Cor Kasbergen, Athanasios Scarpas, Veronique Cerezo
Tire–road interaction addresses safety with respect to braking friction and energy efficiency in the context of rolling resistance. These phenomena are coherent, but their engineering solutions can be contradictory. For example, highly skid-resistant surfaces may not be ideal for fuel economy, but surfaces with low rolling resistance may be prone to skidding. Several experimental and numerical studies have investigated the individual phenomena, but insufficient attention has been paid to studying them coherently. The present study computed braking friction and rolling resistance for various operating parameters and their coherent response for each parameter with the use of a thermomechanical contact algorithm. Micromechanical finite element simulations of a rolling or braking pneumatic tire against selected asphalt concrete surfaces were performed for various operating conditions, such as tire load, inflation pressure, speed, and ambient air and pavement temperatures. The coefficients of braking friction and rolling resistance were found to decrease with the inflation pressure and the temperature and to increase with the wheel load. The braking friction coefficient was found to decrease with the speed, in contrast to the rolling resistance coefficient, which increases with the same parameter. A full-skidding tire registered lower braking friction than a 20% slipping tire. Also, an asphalt surface with higher macrotexture offered higher braking friction and higher rolling resistance, and vice versa.
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Tire–road interaction addresses safety with respect to braking friction and energy efficiency in the context of rolling resistance. These phenomena are coherent, but their engineering solutions can be contradictory. For example, highly skid-resistant surfaces may not be ideal for fuel economy, but surfaces with low rolling resistance may be prone to skidding. Several experimental and numerical studies have investigated the individual phenomena, but insufficient attention has been paid to studying them coherently. The present study computed braking friction and rolling resistance for various operating parameters and their coherent response for each parameter with the use of a thermomechanical contact algorithm. Micromechanical finite element simulations of a rolling or braking pneumatic tire against selected asphalt concrete surfaces were performed for various operating conditions, such as tire load, inflation pressure, speed, and ambient air and pavement temperatures. The coefficients of braking friction and rolling resistance were found to decrease with the inflation pressure and the temperature and to increase with the wheel load. The braking friction coefficient was found to decrease with the speed, in contrast to the rolling resistance coefficient, which increases with the same parameter. A full-skidding tire registered lower braking friction than a 20% slipping tire. Also, an asphalt surface with higher macrotexture offered higher braking friction and higher rolling resistance, and vice versa.
Field experience shows that most road accidents that occur during turning maneuvers arc caused by the loss of vehicle control. The loss of vehicle control is often related to a lack of sufficient friction between the tire and the pavement surface. In experiments and analytical studies, the overall antiskidding performance of a pneumatic tire has been observed to be affected by operating conditions, road texture, and surrounding temperatures. Interactions of these parameters create a complex relationship between their combined effect and the tire's ability to combat skidding. One way to analyze the cornering maneuvers of a vehicle is by means of a validated finite clement tool that can carry both the tire and the pavement properties. Few computational studies have been conducted to study the cornering performance of a rolling pneumatic tire, and none of these studies included the role of pavement surface morphologies in their analysts. In this study, a thermomechanical framework was used to analyze the influence of temperature on cornering friction. The cornering friction coefficient was found to decrease with an increase in the loads and the speeds. The cornering friction coefficient was found to increase with an increase in inflation pressure, sideslip angle, and pavement surface texture depth. The proposed study contributes to an understanding of the cornering performance of passenger car tires.
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Field experience shows that most road accidents that occur during turning maneuvers arc caused by the loss of vehicle control. The loss of vehicle control is often related to a lack of sufficient friction between the tire and the pavement surface. In experiments and analytical studies, the overall antiskidding performance of a pneumatic tire has been observed to be affected by operating conditions, road texture, and surrounding temperatures. Interactions of these parameters create a complex relationship between their combined effect and the tire's ability to combat skidding. One way to analyze the cornering maneuvers of a vehicle is by means of a validated finite clement tool that can carry both the tire and the pavement properties. Few computational studies have been conducted to study the cornering performance of a rolling pneumatic tire, and none of these studies included the role of pavement surface morphologies in their analysts. In this study, a thermomechanical framework was used to analyze the influence of temperature on cornering friction. The cornering friction coefficient was found to decrease with an increase in the loads and the speeds. The cornering friction coefficient was found to increase with an increase in inflation pressure, sideslip angle, and pavement surface texture depth. The proposed study contributes to an understanding of the cornering performance of passenger car tires.
Good pavement macrotexture has a direct influence on vehicle safety during wet weather conditions by improving vehicle traction and braking ability. Apart from the macrotexture, several other factors, such as environmental, tire, and pavement-related characteristics, affect the wet friction. Most experimental studies had a limited scope of reusability as soon as there was a change in any of the other factors. In recent years, the development of powerful finite element tools has made it possible to simulate complex wet tire-pavement Interaction as close as possible to the actual field conditions. However, to the best of the authors' knowledge, none of the past analytical and numerical studies were able to include the actual pavement surface texture in their analysis. This paper describes an approach to study the effect of actual surface morphologies of asphalt pavements on the wet friction coefficient by using the finite element method. Asphalt surface morphologies representative of open-graded mix to close-graded mix were used in the finite element analysis. The finite element model was duly calibrated with the field investigations conducted with state-of-the-art field equipment. The extreme loss of wet friction, which ultimately led to the risk of hydroplaning, was also studied. The analyses were performed for two water film thicknesses, two tread patterns, and two tire slip ratios. The results from the current study can be ased as safety indicators of in-service asphalt pavements under wet and flooded conditions.
...
Good pavement macrotexture has a direct influence on vehicle safety during wet weather conditions by improving vehicle traction and braking ability. Apart from the macrotexture, several other factors, such as environmental, tire, and pavement-related characteristics, affect the wet friction. Most experimental studies had a limited scope of reusability as soon as there was a change in any of the other factors. In recent years, the development of powerful finite element tools has made it possible to simulate complex wet tire-pavement Interaction as close as possible to the actual field conditions. However, to the best of the authors' knowledge, none of the past analytical and numerical studies were able to include the actual pavement surface texture in their analysis. This paper describes an approach to study the effect of actual surface morphologies of asphalt pavements on the wet friction coefficient by using the finite element method. Asphalt surface morphologies representative of open-graded mix to close-graded mix were used in the finite element analysis. The finite element model was duly calibrated with the field investigations conducted with state-of-the-art field equipment. The extreme loss of wet friction, which ultimately led to the risk of hydroplaning, was also studied. The analyses were performed for two water film thicknesses, two tread patterns, and two tire slip ratios. The results from the current study can be ased as safety indicators of in-service asphalt pavements under wet and flooded conditions.