Measurement and Processing of Road Irregularity for Surface Generation and Tyre Dynamics Simulation in NVH Context

Nowadays, finite element tyre models are often used to perform vehicle NVH (noise, vibration, harshness) simulations. To account for the specific operating conditions, a road surface must be properly included in the model. This paper deals with a methodology to experimentally evaluate and process road irregularity measurements, so as to generate a road surface input. These surfaces are used to simulate the tyre/road interaction at the footprint, which is modelled as a contact surface in finite element tyre models. For this reason, a linear profile of the road surface is not suitable for these simulations and the whole surface must be considered. Starting from the measurements taken through a test equipment specifically designed to carry laser sensors and scan road profiles, the Power Spectral Density (PSD) of a specific track is estimated and then interpolated considering piecewise functions. Finally, a model to generate a road surface starting from the measured PSD is developed, discussed and validated.