Rollover Simulation Based on a Nonlinear Model 980208
Research has shown, that accidents involving rollover represent a great safety threat to the passengers. In order to develop restraint systems, a rollover detection mechanism has to be found. Since real world rollover tests are very expensive and difficult to reproduce, a computer simulation of the rollover sequence is very helpful.
This paper presents a multi body rollover model, which was designed to investigate the process of rollover. The model was chosen as simple as possible to allow for short simulation times but still preserve all the important influences.
The model investigates the results of an impact, where the vehicle slides laterally into a rigid barrier with different velocities. Also the influence of different vehicle parameters like the position of the center of gravity on the rollover stability are investigated.
A special focus is put on the suspension system of the vehicle, as it has a major influence on the rollover sequence. An accurate, nonlinear approach was necessary to produce satisfying simulation results. The nonlinearities occur due to geometric constraints. Nonlinearities in spring and damper elements were neglected.
In order to avoid a very complex impact model which would have to describe the plastic and elastic deformations at the tires, a different approach was chosen. Instead of explicitly calculating the acting forces, the linear and angular moments right after the impact was derived, whereas the impact was considered to be a very short impulse.