Evaluating Measured Tire Contact Stresses to Predict Pavement Response and Performance

Author(s):  
Reynaldo Roque ◽  
Leslie Ann Myers ◽  
Bjorn Birgisson

Recent research has indicated that measured contact stress distributions under radial truck tires are highly complex. These stress distributions help to explain near-surface distresses that have become more prevalent since the inception of radial tires, indicating that realistic contact stresses must be considered when pavement response and performance are evaluated. However, because of the complexities involved in measuring contact stresses under tires, obtaining these measurements directly on real pavements is not possible. Consequently, contact stress measurements have been made on systems having rigid foundations with embedded sensors. Therefore, determining whether tire contact stresses measured on a rigid foundation are significantly different from contact stresses under the same tire on an actual pavement is critical. Finite element analyses conducted indicated that both vertical and lateral tire contact stresses measured on rigid foundations accurately represent the contact stresses for the same tire on typical asphalt pavement structures. Some minor differences were observed for thin (50-mm surface) pavements on weak bases, but the correspondence in terms of both distribution and magnitude was still very good. The conclusion was that contact stresses measured by devices with rigid foundations appear to be suitable for predicting response and performance of highway pavements.

Author(s):  
Angeli Jayme ◽  
Imad L. Al-Qadi

A thermomechanical coupling between a hyper-viscoelastic tire and a representative pavement layer was conducted to assess the effect of various temperature profiles on the mechanical behavior of a rolling truck tire. The two deformable bodies, namely the tire and pavement layer, were subjected to steady-state-uniform and non-uniform temperature profiles to identify the significance of considering temperature as a variable in contact-stress prediction. A myriad of ambient, internal air, and pavement-surface conditions were simulated, along with combinations of applied tire load, tire-inflation pressure, and traveling speed. Analogous to winter, the low temperature profiles induced a smaller tire-pavement contact area that resulted in stress localization. On the other hand, under high temperature conditions during the summer, higher tire deformation resulted in lower contact-stress magnitudes owing to an increase in the tire-pavement contact area. In both conditions, vertical and longitudinal contact stresses are impacted, while transverse contact stresses are relatively less affected. This behavior, however, may change under a non-free-rolling condition, such as braking, accelerating, and cornering. By incorporating temperature into the tire-pavement interaction model, changes in the magnitude and distribution of the three-dimensional contact stresses were manifested. This would have a direct implication on the rolling resistance and near-surface behavior of flexible pavements.


2003 ◽  
Vol 125 (1) ◽  
pp. 165-168 ◽  
Author(s):  
Lizhong Xu ◽  
Zhen Huang ◽  
Yulin Yang

Considering the elastic deformation of the rotor and the periodic change of the mesh teeth pair number, the calculation equations of the load distribution for the toroidal drive are presented. Based on the equations, the formulas for calculation of the contact stresses among stator and worm are introduced. By using the above-mentioned formulas, the contact stress distributions for the drive are obtained. The optimal parameters providing for equal contact strength of the stator and worm are determined. These results are useful in manufacture and design of the drive.


Author(s):  
Jorge A. Prozzi ◽  
Rong Luo

Most pavement design and analysis procedures predict performance on the basis of expected pavement damage under traffic loads expected during design life. Some failure criteria are primarily dependent on wheel loads and almost independent of contact stresses. Others are primarily dependent on normal and shear stresses, not on load magnitude. Wheel load is used as a proxy for tire pressure to account for the effect of contact stresses indirectly. In most pavement design methods, tire–pavement contact stress is assumed to be equal to tire inflation pressure and to be uniformly distributed over a circular area. A methodology that explicitly accounts for the effect of tire inflation pressures and the corresponding contact stresses on pavement response is not available. In this research, pavement responses of typical pavement structures under the combined actions of variable wheel loads and tire pressures were evaluated. A multilayer, linear–elastic computer program was used to estimate three critical pavement responses: longitudinal and transverse tensile strains in asphalt and compressive strains in the subgrade. The differences of the strains estimated by the two models were statistically analyzed to quantify the effect of the assumption of uniform stress over a circular shape. The traditional model proved to be reliable to estimate compressive strains in the subgrade layer. The tensile strains in the asphalt layer under actual contact stress, however, were quite different from those under uniform constant stress. Contrary to initial expectation, for the general case, the assumption of uniform stresses is a conservative approach.


2002 ◽  
Vol 128 (2) ◽  
pp. 136-144 ◽  
Author(s):  
Raj V. Siddharthan ◽  
N. Krishnamenon ◽  
Mohey El-Mously ◽  
Peter E. Sebaaly

Author(s):  
Clara Betancourt ◽  
Björn Hagemeier ◽  
Sabine Schröder ◽  
Martin G. Schultz

AbstractWe present context-aware benchmarking and performance engineering of a mature TByte-scale air quality database system which was created by the Tropospheric Ozone Assessment Report (TOAR) and contains one of the world’s largest collections of near-surface air quality measurements. A special feature of our data service https://join.fz-juelich.de is on-demand processing of several air quality metrics directly from the TOAR database. As a service that is used by more than 350 users of the international air quality research community, our web service must be easily accessible and functionally flexible, while delivering good performance. The current on-demand calculations of air quality metrics outside the database together with the necessary transfer of large volume raw data are identified as the major performance bottleneck. In this study, we therefore explore and benchmark in-database approaches for the statistical processing, which results in performance enhancements of up to 32%.


1998 ◽  
Vol 41 (5) ◽  
pp. 1237-1242 ◽  
Author(s):  
H. Jun ◽  
T. Kishimoto ◽  
T. R. Way ◽  
T. Taniguchi

2009 ◽  
Vol 42 (15) ◽  
pp. 2495-2500 ◽  
Author(s):  
Karen L. Troy ◽  
Thomas D. Brown ◽  
Michael G. Conzemius

Author(s):  
Randy B. Machemehl ◽  
Feng Wang ◽  
Jorge A. Prozzi

Truck tire inflation pressure plays an important role in the tire–pavement interaction process. As a conventional approximation method in many pavement studies, tire–pavement contact stress is frequently assumed to be uniformly distributed over a circular contact area and to be simply equal to the tire pressure. However, recent studies have demonstrated that the tire–pavement contact stress is far from uniformly distributed. Measured tire–pavement contact stress data were input into an elastic multilayer pavement analysis program to compute pavement immediate responses. Two asphalt concrete pavement structures, a thick pavement and a thin pavement, were investigated. Major pavement responses at locations in the pavement structures were computed with the measured tire–pavement contact stress data and were compared with the conventional method. The computation results showed that the conventional method tends to underestimate pavement responses at low tire pressures and to overestimate pavement responses at high tire pressures. A two-way analysis of variance model was used to compare the pavement responses to identify the effects of truck tire pressure on immediate pavement responses. Statistical analysis found that tire pressure was significantly related to tensile strains at the bottom of the asphalt concrete layer and stresses near the pavement surface for both the thick and thin pavement structures. However, tire pressure effects on vertical strain at the top of the subgrade were minor, especially in the thick pavement.


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