Developing a Crush Profile Estimate by Balancing Impact Forces

There are many collisions in which the “standard” analysis methods are not sufficient to complete an analysis. Many times the points of rest for the vehicles are not documented or the vehicles were “driven” to the points of rest. There are also cases in which one of the vehicles is repaired prior to being documented. In these cases, there is a method that can be used to establish the approximated speed change of the vehicles.

This method involves using the crush profile of one of the vehicles and balancing the opposing forces across the crush profile to determine an equivalent crush depth on the undocumented vehicle. Using this “balanced forces” method requires a detailed crush profile of one of the vehicles and good stiffness data for both vehicles.

The method is not as accurate as standard methods because of the unknowns, but does yield reasonable results for the speed change severity for the vehicles involved. This paper will discuss the theory of this method and present two (2) example cases.