Safety assessment of a tractor semi-trailer based on handling and stability maneuvers

The UN General Assembly proclaimed the Decade of Action for Road Safety 2021–2030, aiming to prevent at least 50% of road traffic deaths and injuries by 2030. A safe transport system is mandatory for road freight, where heavy vehicle accidents cause more severe personal and financial consequences. In this context, the purpose of this work is to determine the limits of the main handling and stability parameters of a tractor semi-trailer based on maneuvers such as Steady State Cornering (SSC), Double Lane Change (DLC), and Tilt Table Ratio (TTR). The methodology consisted in modeling the tractor semi-trailer using MSC.Adams/Car™ software validated with experimental procedures. The tractor semi-trailer was modeled as a multibody system (MBS), which considers the chassis of a semi-trailer a flexible body using the modal superposition method and the component modal synthesis method, based on an analysis by the finite element method (FEM). In addition, leaf spring suspensions were also considered flexible bodies, and a specific Pacejka tire model was used. Numerical simulations of the SSC maneuver were validated experimentally through RMS values of the rolling angle and lateral acceleration at speeds of 25 and 30 km/h. The DLC maneuver, in turn, was validated at speeds of 35 and 45 km/h, with slight differences observed as a function of human behavior. The simulations indicated that the vehicle may roll over at speeds of close to 38 km/h during SSC and at 55 km/h during DLC, with lateral acceleration between 0.35g and 0.41g, respectively. The TTR simulations showed a corresponding rollover limit with a lateral acceleration of 0.35g. Lastly, the results of this work can be used for safety assessments of the lateral dynamic behavior of semi-trailers.