Articulated haulers are suited for any kind of transports in difficult terrain. The concept was developed from an agricultural tractor in the 1960’s by Volvo. The main features are the hydraulic steering, the individual front and rear frames connected with a rotational hitch joint, all-wheel drive and large tires. These features give the extraordinary terrain capability. Complete vehicle simulations support development of stability, handling and ride comfort properties during early development of the hauler. Complete vehicle simulations can also be utilized to extract design loads. This paper presents the current status in this field.

The complete vehicle MBS simulation model includes flexible bodies, hydraulic system, tires and powertrain. A refined powertrain model in Simulink is used for the analysis presented. The environment is defined by the road and the driver. A comfort track road is used for comfort evaluations and a digitalized endurance test road for load predictions. The driver model aims to follow the given target path and velocity.

Simulation and measurement signals are compared by means of relevant spectra; load ranges, level crossings and Power Spectral Density. A scalar measure is defined by the equivalent value to carry out comparisons between simulations and test. Fatigue load simulations need an accurate dynamic description of the vehicle, capturing low frequency excitation. The results shows that the load simulation captures the frequency peaks below 15 Hz, although there are some differences in magnitude and peak frequency. When simulated and measured equivalent values are compared most entities are in the range between 1/2 and 2 regarding estimated life. Further improvements are possible but the simulated load quality should also be related to other uncertainties in the fatigue evaluation process.