Nonstationary Dynamic Pavement Loads Generated by Vehicles Traveling at Varying Speed

Many of the existing studies on vehicle dynamics assume that vehicles travel at a constant speed on a homogeneous pavement surface. In this paper the effect of nonstationary surface excitation to vehicle dynamics are analyzed. Nonstationary road excitation is resulted from varying vehicle speed when the vehicle travels on a homogenous pavement surface. Frequency-domain methods are no longer valid due to the involvement of varying speed. The state space models are used to characterize vehicle dynamics in the time domain. Two models of vehicle suspension systems are used in the study: a quarter-vehicle model and a half-vehicle model. The former is suitable for analytical treatment because of its simplicity, whereas the latter is more complex but produces more accurate result. Numerical computation is performed to quantify the effects of acceleration and deceleration on dynamic pavement loads. The developed method and computer simulation model can be applicable and integrated into the study of dynamic response of pavement structures.