FEA Study of Belt Angle Effect to Cornering Stiffness and Ply Steer

Performance of vehicle turn and lane change can be evaluated by cornering stiffness. One of many factors affecting the cornering stiffness is belt angle. In 1998, Koishi et al [1] published the findings of cornering stiffness when belt angle is at 0 and 20 degrees, using a finite element code PAM-SHOCK. Results from two cases only are not enough completing the parametric study. With better hardware and software available today than before, the same tire model is re-visited, using new form of numerical procedure — a mixed Eulerian/Langrangian formulation called steady state transport analysis in ABAQUS. Cornering stiffness at the range of 0 to 40 degree belt angle with 5 degree increment is calculated. The results show that three distinct regions exist. At Region I, in which the belt angle ranges from 0–10 degrees, the cornering stiffness increases as the belt angle increases. The cornering stiffness maximizes out and remains flat at Region II, when belt angle is between 10 to 25 degrees. Cornering stiffness decreases as the belt angle increases in Region III, where the belt angle is larger than 25 degree. The existence of Region II may explain the fact that manufacturers prefer around 20 degree belt angle for their tire designs: maximum cornering stiffness and its insensitivity to the belt angle variation. The plot of the predicted ply steer in this study agrees reasonably well with a published experimental data.