Modeling and Analysis of Nonlinear Axial Force Generated by Automotive Drive-shaft Systems Based on Fractal Theory

Abstract

The nonlinear generated axial force (NGAF) of an automotive drive-shaft system is mainly induced by the tripod joint in the drive-shaft system, which will lead to vibration and noise of a vehicle. On the basis of fractal theory, this paper conducts modeling and analysis of the NGAF from the micro level to study the NGAF more effectively. In order to describe the micro contact and friction states between rollers and tracks inside the tripod joint more accurately, a correction method for correcting the distribution function of asperities between rollers and tracks is proposed. Based on the proposed correction method and a calculation model of the NGAF, a fractal model of the NGAF considering rough surface characteristics is established. The fractal model is mainly related to the fractal parameters, the material parameters, the operating conditions and the correction coefficient of the distribution function of asperities. Using Sobol' global sensitivity analysis method, the first order and overall global sensitivities of the fractal model of the NGAF are subsequently analyzed to determine the influence of the factors on the NGAF. The effectiveness of the fractal model and the analytical method for the NGAF is verified by the experiment and calculation examples. The results show that modeling and analysis of the NGAF considering rough surface characteristics are essential to reveal the relationships between the NGAF and the fractal parameters, the material parameters and the correction coefficient from the micro level, which is helpful for the design and analysis of the NGAF of the drive-shaft system.