In this paper, a comparison is made between how the third version of the Calspan Reconstruction of Accident Speeds on the Highway (CRASH3) computes the energy loss of a collision and how this same energy loss is determined by planar impact mechanics (PIM). The main factors that control energy loss as calculated by CRASH3 are the determination of the principal direction of force (PDOF), definition of a common impact point of the two vehicles, the common normal velocity condition, and the tangential correction factor. In the PIM solution, the controlling factors are the definition of a crush surface, definition of a common impact point, common velocity conditions, and the values of normal and tangential coefficients. Experimental collisions (Research Input for Computer Simulation of Automobile Collisions (RICSAC)) are used to provide a basis for comparison. A method is proposed that exploits the features of both methods for vehicle accident reconstructions. (A)
Abstract