Experimental characterization of road roughness input for tyre dynamics simulations

In the framework of road vehicle noise and vibration assessment, the experimental evaluation and the synthesis of artificial road surfaces are typically used for vehicle dynamics simulations and for the estimation of passengers' ride comfort. Indeed, besides the tyre/road interaction and the dynamics of the specific tyre, the road input represents a fundamental aspect for the prediction of the vehicle NVH (Noise, Vibration, Harshness) performances. Moreover, to perform complete simulations of specific environmental conditions, tyre models and road surfaces must be properly combined. In this context, tyre manufactures rely extensively on Finite Element Modelling (FEM) to carry out sensitivity analyses on design parameters. To account for the tyre dynamics in the frequency ranges of interest, very refined meshes are used and, therefore, tyre footprints are modelled as interface surfaces with a significant number of nodes in contact with the ground. To properly run tyre dynamics FEM simulations, this paper proposes a methodology for the experimental evaluation of a road surfaces. Measurements are carried out by means of lasers and a dedicated linear rail system. The Power Spectral Density of the road vertical profile is estimated and, eventually, the road surface was generated by means of a dedicated algorithm.