Comparison of Modelled and Actual Car Dynamic Frontal Crush

The results of the comparison of actual dynamic frontal crush behaviour from initial contact to maximum dynamic crush of 8 cars in 45% frontal overlap and 30 degree rigid barrier impacts at 50 and 56 kph respectively with the predicted responses from an overall frontal crush model are presented. The model used is based on the assumptions of the overall front structure deforming in a geometric manner and of the energy absorption properties in the full width barrier impact being the same as the energy absorption characteristics in other frontal crush configurations for identical average crush depths. The model uses a fundamentally different method of calculating average crush depth to that used in CRASH.

The actual and predicted acceleration-displacement responses show very similar acceleration patterns while comparison of predicted and actual energy equivalent speeds shows for the cars examined that the 98% (+/- 1%) confidence limits between actual and predicted energy equivalent speeds are -8.2 kph to + 6.0 kph for energy equivalent speeds up to 56 kph where energy equivalent speed is the square root of twice the specific energy (energy divided by mass).