A Study of the Steady State Roll-Response of a Large Rear-Dump Mining Truck

The suspensions of large capacity rear-dump mining trucks are required to operate under extremes of vertical load. This imposes conflicting requirements for the fundamental suspension functions in the achievement of adequate isolation of the sprung mass from road unevenness, and acceptable roll stability and directional control during cornering (particularly when fully-laden). The following factors introduce further complications-high centre-of-gravity of the sprung mass of the laden vehicle, highly non-linear characteristics of the suspension spring elements, and relatively close spacing of the rear springs.

The steady-turn roll response of a conventional 218 tonne (240 short ton) payload vehicle has been analysed to determine the loads imposed on suspension spring-elements and tyres, and to establish the roll behaviour as a function of lateral acceleration. Findings are presented in terms of sprung and unsprung mass angular deflections, suspension spring-element and tyre loads and deflections, and the distribution of roll moment between the front and rear suspensions. A non-linear analytical model has been developed to describe suspension spring element characteristics, whereas measured tyre load-deflection data have been used. The analysis has revealed that a high proportion of the total roll moment is taken up by changes in front suspension loads.