In the United States, the National Highway Traffic Safety Administration (NHTSA) routinely measures the force exerted on the rigid barrier in frontal crash tests. Thirty-six load cells on the barrier face measure the distribution of the crash forces. This study examined the load cell barrier data collected during recent years to assess the geometric distribution of the crash forces and the variation in stiffness across the vehicle width. The location of the Center of Force was proposed as a metric for quantitatively describing the geometric properties of the crash forces. The Center of Force location was calculated for each column of load cells. Variations in the Center of Force location across the width of the barrier were examined for typical vehicles. This study applies the aggressiveness metric to a frontal crash from NASS/CDS 1997 in which a passenger car collided with a light truck. The damage patterns, location of damage and extent of damage were examined to assess the contribution of mass, geometry and stiffness incompatibilities, and their contribution to the crash severity experienced by the occupants. Metrics for geometric compatibility based on load cell barrier data were applied to quantify the stiffness and geometric differences. These metrics are summarised in the paper along with an illustrative case. Due to the large variations in the stiffness and the location of stiff points across the front of vehicles, a single metric to characterise stiffness and geometric compatibility may not be possible. (A)
Abstract