Adaptive structure concept for reduced crash pulse severity in frontal collisions

From accident statistics in real-world frontal collisions, it has been shown that a considerable portion of injuries occur in situations without major passenger compartment intrusions and that these injuries can be attributed to the occupant interaction with the restraint systems. To address these types of injuries, a novel front structure concept is proposed. This structure includes a partly detachable front subframe that can actively be released from the passenger compartment and thereby reduce the crash forces and related decelerations. The aim of this study was to quantify the effect of an adaptive front structure on occupant loading in a modern passenger car in frontal crash situations. A simplified finite element model was derived from a full vehicle model in order to run a large simulation matrix spanning from full overlap to small overlap situations. Occupant loading was estimated by using two simplified occupant chest deceleration models, the Volvo Pulse Index and the Occupant Load Criterion. Results suggest that modifying the crash pulse shape can be equivalent to reducing the velocity change in a crash by up to 44%. In relation to scenarios without subframe release, this indicates a considerably lower force required to be applied to the occupant from the restraint system.