A refined dynamic model of a tractor-semitrailer, including the nonlinear tire force and tank swing force, is established, and the fluid force and torque in the liquid tank are obtained through simulation by using the fluid mechanics software Fluent. Two kinds of tests, the tire corner stiffness test and tire roll stiffness test, are designed and performed using the KHAT flat bed test rig for tires, and a nonlinear model of the tire is obtained. The driving vehicle body state and handling stability of the liquid tank semi-trailer are studied through the model. The roll angle and lateral accelerationare used as the rollover characterization parameters. The dynamic lateral load transfer rate (LTR) is used as the rollover index to characterize the rollover threshold. The conclusions are of great significance for running status monitoring, rollover early warning and rollover avoidance controlfor liquid tank semi-trailers.

The movement law data of the tank is  obtained by FLUENT simulation;
Other vehicle parameter motion laws data are  obtained through the joint simulation of SIMULINK and FLUENT.