This report details a programme of practical testing and computer simulation of the roll characteristics of articulated site dumper trucks.
Trials were undertaken at MIRA using a Thwaites 6-Tonne, Power Swivel dumper truck to conduct a range of manoeuvres, at a range of speeds and carrying a range of loads. Each experimental case was modelled in a computer simulation. The modelled and measured results showed good correlation, in particular for manoeuvres incorporating larger bumps (100mm in height) and for circling manoeuvres.
From the measuring and modelling undertaken, it appears that the key contributions to rollover occur when working on uneven ground. Dumper trucks feature very low levels of damping since their only ‘suspension’ is by deformation of the tyres and drive train. On uneven ground, this can produce significant roll angles in response to impact with a bump and this effect can be exaggerated if the natural frequency of the response coincides with another wheel of the truck hitting the same bump.
An initial investigation of the response of dumper trucks impacting a bump when operating on a sloping plane was conducted in the computer model. This indicated that impacting a bump can cause the vehicle to roll over on slopes significantly shallower than the static roll angle of the truck.
This report and the work it describes were funded by the Health and Safety Executive (HSE). Its contents, including any opinions and/or conclusions expressed, are those of the authors alone and do not necessarily reflect HSE policy.
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