Tramping Vibrations in Rigid Axles

Large "undamped" masses of live axles have been thought to cause large fluctuations in wheel-loading. Actually, these fluctuations cannot be accounted for by weight differences between live and dead axles, but rather by rotational vibrations about the longitudinal axis, also known as wheel tramp. The paper analyzes the irregularity functions that govern this vibration, not only the previously understood longitudinal ones, but the transverse as well.

The paper develops the mathematical formulation of forces and movements and subsequently applies the results to wheel-loading and lateral forces. The irregularity functions are described and their effects on wheel-loading, lateral forces, and frictional contact are compared. An example of the application of this computational method is given. The derivations can be applied to different suspension systems.