Tire-Pavement Contact Stress With 3D Finite-Element Model-Part 2: All-Steel Tire on Heavy Vehicles

摘要

Heavy vehicles increase on highways in China year by year. Heavy loads are among the most important factors causing pavement distresses. The distribution of contact stresses between tires and pavement surface greatly influences the initiation and propagation of pavement distresses, especially for the top-down cracking. Therefore, to accurately and precisely describe pavement responses, the distribution of contact stresses should be first investigated thoroughly. This study focuses on simulating the contact stresses between all-steel tires on heavy vehicles and the pavement surface. A 3D finite-element model was proposed and used to simulate the distribution of contact stresses in different conditions of tires, including standstill, free rolling, accelerating rolling, and decelerating rolling conditions. This model was validated by previous study of the authors. There were three loading levels used in this study, including 20 kN, 40 kN, and 60 kN. In the standstill condition, the maximum pressures on pavement surface were simulated as 1.2 MPa, 1.2 MPa, and 2.4 MPa in 20 kN, 40 kN, and 60 kN loading levels, respectively, which were much higher than 0.7 MPa, the standard contact pressure in pavement design specification in China. An interesting phenomenon was observed that when the load passed a certain value, the width of contact area kept constant, whereas the length of contact area was prolonged. And the length of the contact area prolonged linearly with the increase of load. Based on this phenomenon, the Hertz contact theory was applied to simplify the traditional 3D finite-element model. In the simplified model, the complicated 3D all-steel tire was simplified to an equivalent medium. The 3D finite-element model and the simplified model were compared with the analytic method. This indicates that the simplified model can simulate the contact stress of all-steel tires closely to the analytic results (no more than 10 % difference) and greatly improves the calculation efficiency.