Citation

Brach RM. Accid. Anal. Prev. 1983; 15(2): 105-120.

Copyright

(Copyright © 1983, Elsevier Publishing)

DOI

unavailable

PMID

unavailable

Abstract

Various methods are used to calculate unknown velocities and velocity changes for the collision of automobiles. Most methods use some form of the equations of impulse and momentum from mechanics. In this paper the planar impact between two vehicles is modeled through the use of six algebraic equations. These equations relate the three velocity components of each vehicle at the beginning of contact to the three velocity components of each vehicle at separation using two coefficients of restitution and an equivalent coefficient of sliding friction. The first part of the paper contains a discussion of some of the fundamental assumptions connected with the use of impulse and momentum concepts for collision analysis. A summary of the derivation of the six model equations is presented. In a second part of the paper, the equations are solved for the conditions corresponding to two experimental collisions. Values of the three coefficients are systematically varied to assess their effect on the vehicle velocity changes. A listing of a computer program is furnished, written in the BASIC language. The program can be used to solve the model equations for the final velocities given the initial velocities and coefficients. The vehicle properties and collision geometry must also be known.