Abstract

A new approach to determine an optimum tire contour was developed and was applied to improve various tire performances following the corresponding objective function and constraints. Although several tire contour theories have been proposed in the past, some of them were based on a simple model and could not be used to improve tire performances effectively. On the other hand, others were not described by an equation and their application was limited. In the new approach, the optimization technology was applied to efficiently obtain the optimum contour by minimizing an objective function, while satisfying the constraints. The new approach was verified to be able to improve various tire performances.

Abstract

A new approach to determine the optimum compound characteristics in each tire material is developed and applied to improve various tire performances following the corresponding objective functions and constraints. In the new approach, optimization technology is combined with a finite element method so that the optimum compound characteristics in each tire material are obtained by minimizing an objective function, while satisfying the constraints. Hence, the targets of rubber characteristics in each material of a tire can be determined by the proposed approach to improve tire performance. When we optimize the compound characteristics in each element of a tire model, the number of design variables becomes more than a few hundred. Therefore, the sensitivity of the stiffness matrix in the optimization is obtained by a semi‐analytical (or implicit differentiation) method and computational time is greatly reduced compared to the finite difference method. The new approach is applied and verified to improve the rolling resistance of a tire. Furthermore, we can obtain guidelines for a new topological tire structure by the Young's modulus optimization, considering that the rubber material should be removed from the initial tire design, if the optimum Young's modulus is almost zero at the element.

Abstract

A finite element‐based method to analyze the severity of internal cracks in cord‐rubber structures is presented. The method includes materials testing to characterize rubber fatigue behavior, a global‐local finite element analysis to provide the detail necessary to model explicitly an internal crack, and use of the J‐integral and virtual crack closure techniques for energy release rate evaluation. Analysis of the multiaxial and cyclic fracture situation is carried out by considering the cycle of each mode of fracture separately and then combining the effect of each mode to determine the total effect. Crack growth rates in the structure are assumed to be the same as the crack growth rate in a laboratory specimen at the same level of cyclic energy release rate. Results are presented for a material change in a critical tire region.

Abstract

Recent advances in rubber compounding as well as a more advanced understanding of deflated tire mechanics, combined with consumer demand for increased vehicle safety and convenience, have led to the development of self‐supporting tires. Self‐supporting tires, which are available for lightly loaded sport vehicles, are now available for the more common 60‐series tire and the luxury car segment.

This paper highlights some of the methods used to develop the P225/60R16 MXV4 ZP and provides information on its application and performance. Modeling for the zero‐psi tire and factors that influence performance (speed, load, cornering, and ambient conditions) are discussed.

Abstract

Using a flat‐belt tire test machine, this study investigated causal factors in the wear of tire tread. To ensure the success of the experiment, the accuracy of the testing device was improved and the trial conditions were kept under close control. As a measure against sticky particles of worn rubber clinging to the surfaces of the safety‐walk and tires, a uniform amount of mica powder was electrostatically coated onto the tire tread surfaces. Surface whiteness was measured and controlled automatically to maintain a constant level. The amount of wear was calculated by weighing the tire on a precision six‐order electrical balance sensitive down to 0.1 g. Consequently, in a relatively short time it was possible to ascertain measurable rates of wear, and the effects of main factors on the wear rate (the weight reduction per unit distance travelled) of car tires, the linear wear rate (the weight reduction per unit distance slid), the energetic wear rate (the weight reduction per unit energy lost), and friction coefficient were evident.