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Dynamic fluid slosh and its influence on the dynamic roll stability of a partially filled tank truck has been investigated through a field test program undertaken jointly by the CONCAVE Research Centre and Transportation Technology and Energy Branch of Ontario Ministry of Transportation. The paper describes the test methodology, instrumentation, data acquisition, fluid slosh behaviour, and its influence on the directional response of the tank truck. The data acquired during different directional maneuvers is analyzed to highlight the fluid slosh and its impact on the dynamic load transfer and roll stability of the vehicle. The magnitude of dynamic load transfer, derived from the video records of the dynamic fluid movement, is presented and discussed for various tank fill levels and directional maneuvers. The test results revealed that the magnitude of dynamic fluid slosh is strongly related to the vehicle speed, lateral and longitudinal acceleration, and the fill level.

The computation of dynamic slosh forces arising due to liquid motion within a partially filled tank is quite important in analyzing the directional behavior of tank trucks during various highway maneuvers. The most precise computation of liquid motion and the associated slosh forces involves solving complex non-linear fluid mechanics equations and is extremely cumbersome. The motion of liquid within a partially filled tank is herein investigated by representing the fluid slosh through an equivalent mechanical system using a pendulum analogy model. The model parameters are computed based on inviscid fluid flow conditions and the dynamic fluid slosh forces arising due to the dynamics of the vehicle during a given maneuver are computed using the equivalent mechanical system. The dynamic fluid slosh forces and moments are then integrated into the vehicle dynamics model to study the directional response characteristics of tank vehicles.

A dynamic stability analysis model of a five-axle tractor semitrailer vehicle is developed using the MATLAB/SIMULINK application tool. The linearized vehicle model is utilized to investigate the impending instability limits under various design, and operating conditions. Computer simulations are performed for step steer and a typical highway maneuver as input conditions to generate the yaw response characteristics. The model development is accomplished in a modular form to accommodate interactive re-runs of the model with design variations. SIMULINK modeling provides greater flexibility in development and incorporation of active control system modules in the model in order to investigate possible enhancement of vehicle stability limits.