Dimensionless Analysis of Rearward Amplification of Trucks with Single and Double Trailers: A Frequency Analysis

This article provides a dimensionless analysis of the rearward amplification (RA), that is, the ratio of peak lateral acceleration between tractor and rearmost trailer, of commercial trucks with single and double trailers. Through the nondimensionalization, a series of dimensionless parameters that are critical to the lateral and yaw dynamics of the vehicle are determined, which primarily includes vehicle mass ratio, momentum ratio, wheelbase ratio, and longitudinal center of gravity (CG) position ratio. A series of simulations are performed with sinusoidal steering maneuvers with various frequencies ranging from 0.01 Hz to 0.6 Hz. A frequency analysis of the effect of the dimensionless parameters on the RA for the single- and double-trailer trucks is provided. The simulation results suggest that increasing the trailer load causes a larger RA at the steering frequencies below 0.5 Hz. In addition, longer trailers could reduce RA by providing additional damping effects that stabilize the trailer’s yaw movement. It is also found that trailer rearward loading contributes to a larger RA for a single trailer, whereas it has the opposite effect in a double trailer. It is determined that the trailer wheelbase has a larger effect on RA than the trailer CG longitudinal position.