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The directional dynamics of partially filled articulated tank vehicles is investigated via computer simulation assuming constant forward velocity. The directional response characteristics of an articulated tank vehicle is investigated for various steering manoeuvres and compared to that of an equivalent rigid cargo vehicle to demonstrate the destabilizing effects of liquid load shift. It is concluded that during a steady steer input, the distribution of cornering forces caused by the liquid load shift yields considerable deviation of the path followed by the tank vehicle. The lateral load shift encountered in a partially filled tank vehicle during lane change and evasive type of highway manoeuvres gives rise to roll and lateral instabilities.

General purpose tank vehicles often carry partial loads in view of variations in the weight density of the liquid cargo and are thus subject to slosh loads during highway manoeuvres. The magnitude of destabilizing forces and moments due to liquid slosh is strongly related to a number of vehicle and tank design factors, such as tires, suspension, articulation mechanism, weights and dimensions, tank geometry and fill level. The rollover threshold of the tank vehicle is compared to that of an equivalent rigid cargo vehicle to demonstrate the destabilizing effects of liquid slosh. The rollover threshold of the tank vehicle is evaluated for a number of tank design factors. Influence of tank size and cross-section on the rollover threshold of the tank vehicles is investigated. The study concludes that the lateral load shift and thus the rollover threshold is strongly related to the tank cross-section geometry.

A six degrees-of-freedom ride dynamic model of a cab-over-engine supported on elastomer mounts is developed using lumped parameters. The lumped parameter model is analyzed for its free vibration response, while assuming the cab structure to be rigid. A finite element model of the suspended cab is developed and analyzed to establish the influence of flexibility of the cab structure on the ride dynamics of the tilt cab. The vibration modes of analytical lumped parameter and finite element models are compared to the dominant ride frequencies of the vehicle measured in the field. The lumped parameter model is then modified to achieve a comprehensive ride dynamic model for its further use in ride performance analyses.

Ride quality of articulated vehicles is investigated via computer simulation in view of secondary suspension parameters. A tractor-semitrailer vehicle is modelled incorporating primary as well as secondary suspension. The ride vibration levels at the cab floor and at the driver-seat interface are evaluated using power spectral density approach. The effect of various vehicle parameters, such as secondary suspensions, primary suspensions, axle loads and tires on the vehicle ride quality is presented, and the significance of secondary vehicle suspension is specifically emphasized. A software package is developed to evaluate and assess the ride performance of articulated vehicles with suspended seat and cab. A limited validation of the computer ride model is achieved via field measurements.