Analysis of roll angle dynamic behavior in heavy dump trucks during lifting process based on MBD-DEM coupling

This paper proposes a dynamic modeling method for heavy dump trucks during lifting operations on sloped terrains. Traditional linear models are limited in capturing system nonlinearities and external disturbances, which are addressed in the proposed approach. Both the rear-dump truck and the side-dump truck are selected as the research objects. A theoretical dynamic model is first established using the Lagrange method, considering the roll motion of the sprung mass and the cargo system as well as the cargo sliding behavior. Subsequently, a multi-body dynamics model is developed, incorporating suspension springs and cargo box torsional stiffness to describe the rigid-flexible coupling characteristics of the vehicle. The discrete element method is employed to calibrate particle contact parameters for different types of cargo, enabling accurate modeling of the unloading process. A co-simulation model under sloped conditions is then established and validated against the theoretical model. Finally, a comparative analysis is conducted under rear-discharge and side-discharge modes. The analysis focuses on centroid height, roll angle, cargo mass, and moment of inertia. The results reveal the influence mechanism of discharge modes on system stability.