Simulation of Road Surface Profiles

Abstract

This paper presents a novel technique for the simulation of shock and vibrations related to road surface irregularities. The technique is based on a recently developed universal road profile classification scheme, which is one of the main outcomes of a project aimed at better understanding the statistical nature of road surfaces and their interactions with road vehicles. The method, which focuses on the nonstationary and non-Gaussian nature of road profiles, is described along with an analysis procedure developed and implemented to automatically detect and extract transient events from the road spatial acceleration data as well as identify stationary segments of similar roughness (RMS). The paper shows how the concept of treating road surface irregularities as two fundamental components, namely, steady-state road surface irregularities and transient events, can be employed for classification and simulation purposes. The simulation technique is based on a universal statistical model of road surface profiles that characterizes the power spectral density of the underlying irregularities, the probability distribution function of the RMS level using the offset Rayleigh distribution function, and the transient density. The transient events are generated with random amplitudes according to the Gaussian distribution, the mean and standard deviation of which are functions of the underlying RMS level. This paper shows how these two components can be combined to numerically synthesize a process that faithfully represents the nonstationary, transient-laden nature of road surface profiles. The synthesized process can be physically realized on a vibration shaker to simulate road profiles.