The paper presents a simulation study on the effects of varied crash speed (due to pre-crash deployment of Automated Braking System) on the injuries sustained by vehicle occupants in a subsequent crash. The methodology used for the study, has been previously outlined (1), showing the effects of altered pre-crash conditions due to emergency braking. The present study focuses on exploring the adaptability potentials of existing state-of-the-art restraint systems to protect occupants even better under different collision conditions created by deployment of AEB.
In the simulation study, a generic passenger vehicle (d-class) is exposed to a reference 56 km/h USNCAP Full Width Frontal test preceded by emergency braking of about 0.8g derived from vehicle testing. In order to investigate the effect of collision speed on the efficiency of occupant protection, a crash pulse scaling method was developed and accordingly applied. This allowed to investigate the case at every random crash speed below 56 km/h.
All simulations are performed in MADYMO (a multibody, numerical solver) and use 3 different 50%-ile occupant models: Active Human Model (AHM), Hybrid III and THOR.
The results show significant capacities of a DOE optimized safety system in reducing AIS 2+ injury risk for the varied collision speed, especially in the range of 25-40 km/h delta V.
The introduction of adaptability of restraint system settings to the varied collision speeds (different than specified by test protocols) resulted in significant improvement of occupant protection. It is thus anticipated that introduction of further system adaptations to the other crash condition parameters will have similar or even more pronounced beneficial effect. Further studies will be focused on adapting restraint systems to varied occupants parameters (size, BMI, age), occupant out of position and also collision conditions e.g. crash angle or crash severity based on predictive detection and classification of collision participants.