Lateral Stability of Road and Rail Trailers

Abstract

The conditions for the lateral stability at a highway or rail trailer are investigated analytically and experimentally with a laboratory size trailer. The motion of the trailer is expressed in two degrees of freedom, the lateral and angular displacements of the trailer. The oscillation was found to be a self-excited vibration which is very dependent upon the lateral springing at the towing pivot point. The variables are expressed as dimensionless parameters. For conventional trailer loading, the most important variables are the damping ratio as a function of the Strouhal number, sω/V, and as a function of a dimensionless energy term, μGz/V2 . As higher values of sω/V and μGz/V2 are reached (for example, lower velocity), less damping is needed for stable operation. Although the relationships have not been established precisely, there is good correlation.