ABSTRACT The contact patch between tire and road surface has a direct impact on tire grounding performance. Acquiring tire grounding performance either by testing or simulation is not only time intensive but comes at a high cost. This paper proposes an effective means of evaluating tire grounding performance based on the tire-ground contact pressure distribution. This paper adopts fifteen characteristics to describe the tire-ground contact patch in which twelve structural schemes were designed for a certain type of tire. By using the simulation test method, the grounding performance characteristics such as grip performance, rolling resistance, wear performance, and the tire footprint characteristics were obtained. Correlation analysis was used to explore the relationship between tire grounding performance and footprint characteristics. Based on the correlation analysis and expert judgement, the analytic hierarchy process (AHP) model for comprehensive grounding performance evaluation of a tire was constructed. Then judgment matrix of the AHP model was established, and the consistency or otherwise of the judgment matrix was verified. The model was then used to evaluate and predict the four design schemes of tires. The evaluation results were in good agreement with the simulation test results, which shows that the construction method of the tire comprehensive grounding performance evaluation system proposed in this paper is practical. It is also evident that grounding performance evaluation of a tire based on the tire footprint is feasible.
ABSTRACT In order to clarify the contradictory mechanism between tire rolling resistance and grip performance, 10 205/55 R16 radial tires with different tread patterns were selected as the research objects. Based on digital image correlation method, the pressure and deformation distribution in the contact area of test tires were obtained and the relevant grounding parameters were extracted. The partial least square regression (PLSR) method was used to establish the relationship between the identified grounding parameters and tire performance indicators. Using the bootstrap resampling method, the significance test of the PLSR coefficients were carried out, and the grounding characteristic parameters with significant explanatory effect on the performances were selected, identifying the main function area for the two performances. The results show that in order to improve the grip performance of the tire, it is necessary to reduce the transverse tensile strain of the tread in the contact area and increase the longitudinal tensile strain of the tread; but, with the increase of the longitudinal tensile strain, the rolling resistance of the tire will also increase, which leads to the contradiction between tire rolling resistance and grip performance.
ABSTRACT With the progress of noise control of engines and the rise of new energy vehicles, the severity of tire noise has been increasingly highlighted. Recently, the nonpneumatic tire (NPT) has drawn attention because of its novel structure design that surpasses traditional tires in anti-explosion, maintenance-free, and low rolling resistance characteristics. However, with an open-side structure and violent air impact at the flexible spokes, an NPT emits greater aerodynamic noise than a pneumatic tire during high-speed rolling, which results in an adverse effect on the riding comfort of vehicles. The arrangement pattern of flexible spokes in an NPT plays an important role in the generation of aerodynamic noise. In this study, the aerodynamic flow around NPTs, which were in contact with the ground, rolled at a speed of 80 km/h, and had different arrangement patterns of spokes, was investigated using the Reynolds-Averaged Navier-Stokes method and Large-Eddy Simulation. Then, the far-field aerodynamic noise of different NPTs were calculated using Ffowcs Williams-Hawkings equations in the acoustic model of ANSYS-Fluent. The influence of spoke arrangements on the flow pattern and aerodynamic noise was analyzed. Based on the results, we propose an optimized design of spokes that can enhance the aero-acoustic performance of NPTs.
ABSTRACT Tire inflation pressure loss is inevitable during tire service time. The inflation pressure loss rate (IPLR) is widely used to estimate the inflation pressure retention performance of a tire. However, an IPLR test is a time-consuming process that lasts 42 days for a passenger car tire and 105 days for a truck/bus tire. To perform a thorough study of the tire pressure loss process, based on Abaqus software, a finite element model was developed with tire geometry inputs as well as tire material inputs of both mechanical and permeability properties of the various rubber compounds. A new method—the ideal material method—is proposed here to describe the transient tire pressure loss. Different from the previous isotropic models, the cord–rubber system is described using orthotropic diffusivities, which were determined through air-pressure-drop tests then applied in the finite element model in this article. Compared with the standard IPLR test, the difference between the tire IPLR test and the simulation result is within 5%.
ABSTRACT The wide-base tire is a relatively new design that originated to replace dual tires because of its potential for improved performance. However, during the construction process, the wide-base tire is more likely to experience tread deformation and uneven stress distribution. The goal of this study is to incorporate numeric techniques for the construction and design optimization of a wide-base, heavy vehicle, pneumatic tire. First, four conditions of the tire (385/55R22.5)–building process, including gluing of components on the main drum, gluing of components on the auxiliary drum, green tire, and finalizing the capsule vulcanizing machine, were simulated using finite element analysis. Second, to solve the difference in the tire's (435/50R19.5) material distribution between the real manufactured structure and the theoretical structure, the curved surface drum-building method and the parameters of the curved surface drum were determined by tire construction simulation. In this article, we present the method for collecting tire material, the measurement process, the analysis method, some general results, and statistics on the wide-base tire. Finally, validation of results of the simulation and measurement are given.