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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.

Optimal trailer design for tractor-trailer transportation depends on accurate and reliable estimates of typical lifetime loading duty cycles. On-the-road testing was done to measure the vertical acceleration response of three different trailers in forest logging conditions. The test conditions included various trailer axle and load configurations, weight transported, and road surfaces including both gravel and paved roads. It was concluded that the rigid trailer body bounce and pitch, the non-rigid body trailer bending, and the wheel hop are the primary components of the vertical response. These results establish approximately what types of operational amplitudes are to be expected for these operations and will provide the basis for the development of a more general trailer frame load prediction model.

In this paper the effects of design parameters on the performance of an electric vehicle are presented. A detailed mathematical model was established using governing vehicle dynamics equations. Ideal energy storage systems were modelled with high order polynomial equations and represented graphically in the form of Ragonne curves. This was followed by the development of a simulation program which was utilized to optimize the design parameters, such as specific energy and mass of the storage system, electric motor operating voltage and electric drive final gear ratio. The effects these parameters had on the objective functions, namely range, acceleration, specific consumption, battery cycle life and cost were investigated. The outlined optimization process is presented in a manner which enables the designer to optimize electric or hybrid electric vehicles.

Low frequency terrain induced vibrations transmitted to the off-road vehicle operators are quite severe and exceed I.S.O specified “fatigue decreased proficiency” limits. In this paper, the ride improvement of an agricultural tractor is sought through effective designs of passive seat suspensions. The dynamic analysis of existing bounce suspension seats is carried out to establish its ride performance behaviour. Optimal bounce seat suspension parameters are selected with an objective to maintain the ride vibration levels within 4 hours exposure “fatigue decreased proficiency” limits. The roll and pitch ride vibrations, perceived by the operators, can be attenuated through a gimbal arrangement mounted to the bounce suspension seat. The optimal parameters of the combined seat isolator are selected using parametric optimization techniques. Also a horizontal isolator, attachable to the bounce or the combined seat isolator, is configured.

The unique difficulties associated with low frequency and large amplitude ride vibrations of off-road tractor are summarized. Concept of a cab suspension system for improving the ride quality of off-road tractors in the bounce, longitudinal, lateral, pitch and roll modes is explored. Influence of suspension parameters on the ride performance is presented followed by selection of optimal suspension parameters. It is shown that a cab suspension would provide improved performance in the longitudinal and pitch modes alone. Ride analysis of the cab suspension with a sprung seat reveals satisfactory bounce ride. Roll and lateral ride of the off-road tractor can be improved significantly through alterations in the cab geometry. The ride performance of the optimal suspensions is assessed with reference to ISO (International Standards Organization) specified “fatigue decreased proficiency” (FDP) boundaries.

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.