In the mixed lubrication regime, the roughness effects are very important due to the presence of interacting asperities. Patir and Cheng derived a method that rewrites the Reynolds equation in terms of the averaged flow factors. The flow factor method has been used in many applications to demonstrate the effects of surface roughness on the mixed lubrication. In this study, the flow factors considering the elastic deformation of the rough surface due to a direct contact of asperities are calculated. The pressure flow factor and the shear flow factor are evaluated for the rough surfaces with both Gaussian and non-Gaussian height distributions. The results show that there is a large difference of flow factors between the rough surface considering the elastic deformation and that assuming the rigid body due to an increase of the film thickness and a decrease of the slope of asperities after the elastic deformation of asperities.

A finite element modeling technique is employed in this paper to predict the force transmissibility of tire-cavity-wheel assembly under a free-fixed condition. The tire and wheel force transmissibility is factor in structure borne road noise performance. In order to improve structure borne noise, it is required to lower the 1 st peak frequency of force transmissibility. This paper presents an application of finite element analysis modeling along with experimental verification to predict the force transmissibility of tire and wheel assembly. The results of finite element analysis for force transmissibility are shown to be in good agreement with the results from the indoor test. In order to improve structure borne noise, it is required to lower the 1 st peak frequency of force transmissibility. And, the effect of the tire design parameters such as the density and modulus of a rubber and the cord stiffness on the force transmissibility is discussed. It is found that the prediction of the force transmissibility model using finite element analysis will be useful for the improvement of the road noise performance of passenger car tire.

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