The dynamic rollover threshold - a heavy truck sensitivity study

Abstract

Knowledge of rollover mechanics, which is required in heavy truck development, commonly relies on a static analysis, providing the steady-state rollover threshold, SSRT. In a rolling vehicle, kinetic energy is always present and that deteriorates the analysis of roll stability from SSRT and implies the need for a dynamic rollover threshold, DRT, as a complement. A method to determine DRT is presented and a parameter sensitivity study is applied. The influences on SSRT and DRT, including interaction effects, from roll stiffnesses and roll centre heights, are calculated. Results show that a rigid truck and a tractor semitrailer combination are unequally sensitive to parameter changes. Design changes can hence affect SSRT and DRT differently, which indicates that two vehicles can be equally stable statically but differently dynamically. Therefore, if DRT is not analysed, a redesign of a vehicle can deteriorate roll stability even though it appears to improve it.