Energy Basis for Collision Severity

This paper presents an objective technique for estimating the severity of automobile collisions. The vehicle damage and the dynamic force-deflection characteristics of the vehicle structure are used to estimate the energy absorbed in plastic deformation of the vehicle. This energy can then be expressed as an “equivalent barrier speed” (EBS). The development is limited to frontal damage, although the technique is general and could be extended to side and rear damage.

Data are presented relating residual crush and impact speed for full frontal barrier tests to provide the basis for a simple model of the force-deflection characteristics of the vehicle front structure. EBS is then estimated by integrating this force-deflection characteristic over the deformation of the field vehicle.

The results of this model are compared with test data to indicate the types of damage patterns for which the model appears valid. Calculations are made for damage patterns resembling angle and offset barrier impacts, and the computed EBS is compared with the actual impact speed. For both types of test, the errors seem within normal test variability.