Directional Dynamics of a Partly-Filled Tank Vehicle Under Braking and Steering 2000-01-3477

Dynamic behavior of a partly-filled liquid cargo vehicle subject to simultaneous application of cornering and braking maneuvers is investigated through computer simulation. A three-dimensional quasi-dynamic model of a partly-filled tank of circular cross-section is developed and integrated into a comprehensive three-dimensional model of an articulated vehicle to study its directional response under varying steering and braking inputs, fill volumes and road surface friction. The liquid load movement encountered under combined steering and braking is expressed in terms of variations in the instantaneous c.g. coordinates and mass moments of inertia of the liquid bulk, assuming negligible influence of fundamental slosh frequency and viscous effects. The dynamic response characteristics of the partly-filled tank vehicle under braking and turning are presented in terms of resulting cargo load shift, moments induced by the cargo movement, load transfer ratio, yaw and roll response, and braking performance of the vehicle. The response characteristics of the partly-filled tank vehicle are compared with those of an equivalent rigid cargo vehicle to demonstrate the impact of the liquid load shift under combined turning and braking maneuvers. The results of the study reveal that a partly-filled articulated tank vehicle, subject to braking in a turn, is more susceptible to rollover on dry roads, while it exhibits a higher propensity of trailer swing on slippery roads.