A generally applicable 3D truck ride simulation with coupled rigid bodies and finite element models

Abstract

The aim of this paper is to present a three dimensional ride simulation for a medium weight truck equipped with two axles. The dynamics of both a rigid body and a flexible frame structure are considered in the vehicle model. The road surface irregularities are modelled as stationary Gaussian random excitations taking into account the cross correlation between the vehicle axles and tracks. The free-free modal properties of the frame structure have been calculated using the FEM (finite-element method) considering two different configurations for the vehicle frame. The results from the FE models are incorporated with the general vehicle model to study their effect on the vehicle ride behaviour. The equations of motion of the general vehicle model have been formulated applying the Lagrangian approach and the modal superposition theory. Random responses, including power spectral densities and root mean square values, are calculated and analysed. The results covered 23 response variables including driver, cab and body accelerations and the induced dynamic forces in the cab and main suspension systems and tyres. The results showed that the structure dynamics of the frame strongly affects several response variables. Moreover, it has been found that the present simulation technique is practical, powerful, and economic, and can be commercially used for the assessment of truck dynamics. Conclusions and recommendations for further work are given.