F2008-08-129
The Interdependence between Occupants and Passive Protection Concepts for Rollover Injury Mitigation
Rollover accidents are complex crash incidents and reflect more than other types of crashes the interaction of the driver, road, vehicle and environmental factors. A rollover is a crash in which a vehicle revolves at least one-quarter turn (which would be onto its side), regardless of whether the vehicle ends up laying on its side, roof, or even returning upright on all four wheels. In order to protect the vehicle occupants from hard contact with vehicle body parts or external objects protection devices such as side or curtain airbag were introduced.
The paper presented here will illustrate the interdependence between protection concepts and occupants. There are three important parameters affecting the system compost of occupant and protection device. The passenger with his individual measures like size, weight or its constitution is one of these three parameters. Furthermore, environmental influences such as pre-crash events, vehicle-rollover accident scenarios, occupant contact with vehicle body parts, basic vehicle geometry and passenger compartment stiffness are the second important parameter - and the passive protection concept itself as the third parameter.
During a contact between the occupant and the protection concept the occupant is subjected to local, time-variable loads. If the protection concept reduces the load to the level of the injury value limits und below, it represents a reasonable protection device. If the loads are above the injury limits, the protection device touches its own physical limits. If the transgression of the load limits is induced even by the protection system itself, the protection device represents a not to underestimated source of injuries. As a consequence, the different parameters of the protection concept need to be revised.
American accident analysis systems National Automotive Sampling System - General Estimates System (NASS-GES) from the National Highway Traffic Safety Administration (NHTSA) in combination with numerical simulation techniques based on Adams and Madymo software have been used to evaluate the nature of various vehicle rollover accidents and to understand the consequences of the interaction between the three main parameters.
Session: Occupant & Pedestrian Protection II