A multi-body dynamic method to analysis of the rollover thresholds and roll safety thresholds of tractor semi-trailer vehicles based on roll safety factor and roll angle of vehicle bodies

The article aims to use the multi-body dynamic method to analyze the Dynamic Rollover Threshold (DRT) and Roll Safety Thresholds (RSTs) of a tractor semi-trailer vehicle using the Roll Safety Factor (RSF) and the roll angle of the vehicle bodies. A full dynamics model of a 6-axle tractor semi-trailer vehicle is established using the Multi-body Dynamic method. This model is then used to simulate and evaluate the rollover state of the vehicle. From these simulations, 3D maps of the RSF and roll angle of the vehicle bodies at the time when the RSF reaches its maximum value are created. These maps are then used to propose a method for determining the DRT and RSTs based on the proposed values of RSF (RSF_Prop). When RSF_Prop equals 1, the corresponding roll angle value is determined as the DRT. Depending on the purpose of the system (warning or control), different RSF_Prop values can be selected to determine the corresponding RSTs. When RSF_Prop equals 0.85 is chosen, the control threshold ranges from 4.188 to 4.844 degrees for the roll angle of the tractor body and from 4.302 to 5.130 degrees for the roll angle of the semi-trailer body. Similarly, when RSF_Prop equals 0.7 is chosen, the warning threshold ranges from 3.0534 to 3.580 degrees for the roll angle of the tractor body and from 3.091 to 3.701 degrees for the roll angle of the semi-trailer body. When RSF_Prop equals 0.6 is chosen, the warning threshold ranges from 2.635 to 2.680 degrees for the roll angle of the tractor body and from 2.663 to 2.680 degrees for the roll angle of the semi-trailer body. These RSTs can then be used as the basis for designing warning or control systems, with the warning parameter being the roll angle of the vehicle bodies.