The Method Of Predicting Tire Mechanical Characteristics On The Flat-road Based On The Drum Test Data

The two most common conditions are turning and straight in the car driving,and the corresponding tire mechanical characteristics are cornering and rolling resistance properties. So it is very important no matter for the tire research or the vehicle modeling of accurate accessing to the tire cornering and rolling resistance properties. When the tire cornering or rolling resistance properties are measured on a drum test machine, the surface curvature would affect the tire mechanical characteristics. The problem of surface curvature had caused the researchers’ attention as early as the 1970 s, and they attempt to find a formula to convert the tire cornering and rolling resistance properties on curved surface to comparable flat surface. But until now, it has not been realized. Therefore, in this paper the method of predicting tire mechanical characteristics on the flat-road based on the drum test data was researched by the means of finite element techniques,in order to eliminate the influence of the surface curvature. The main contents of this paper were carried out as follows:1. The tests study of the tire cornering and rolling resistance properties on drum and flat surface. Improving the external drum test machine and making it can to do the cornering test. On this basis, testing was conducted on this equipment and obtained the tire cornering and rolling resistance test data on curved surface. At the same time, the same testing was measured on the flat test machine, and the test data comparison was made from drum to flat surface, which made clear that what the general influence tendency is made by surface curvature on the cornering and rolling resistance properties. Then,the existing transformation formula’s prediction accuracy was calculated and analyzed based on the test data and its insufficiency was pointed out, which showed the necessity for study and led to the research ideas of this paper.2. The build of the tire finite element model(FEM).The whole process of establishment of FEM was introduced, including software selection, 2D mesh division, the generation of 3D model and the determination of material parameters. The meshing instructions and the method of rubber and steel material mechanical properties test and parameters determination were emphasized. Also, rubber material parameters identification tool was developed in this paper.3. The prediction of the tire cornering properties on flat-road. Firstly, according to the cornering test data out of drum test machine to adjust the tire FEM to let its lateral force simulation precision more than 90% and aligning torque simulation accuracy over 85%. Secondly, using this model to predict the tire cornering characteristics on flat surface, and extend the forecast conditions to various static stiffness, steady longitudinal slip, effective rolling radius and non-steady step responses to side-slip angle. Finally, the prediction accuracy of the revised tire FEM was verified by comparing the simulation results with the experimental results. It provided a new way for further study to eliminate the influence of curvature on the tire cornering characteristics of flat surface.4. The prediction of tire rolling resistance properties on flat-road. This paper elaborated on the definition of tire rolling resistance and rolling resistance moment, and found an error in GB while deriving the rolling resistance formula, which was proved by the means of ”proof by contradiction" and "finite element method". Subsequently, researched the relationship of rubber viscoelastic and tire rolling resistance, and further modified FEM based on the rolling resistance test data from drum test machine. In addition, the correctness of the correction method and the accuracy of the model was verified through comparing the rolling resistance simulation results on the curved surface with the measurement results. Finally, simulated the rolling resistance on the flat-road and compared the simulation results with the test results, and found that the simulation accuracy was above Freudenmann, T. formula conversion accuracy, which showed the advantages of the research methods proposed in this paper.