The Traffic Accident Reconstruction Origin -ARnews-

Re: Crush Analysis

Ed Livesay (EdLivesay@worldnet.att.net)
Fri, 28 Jun 1996 13:51:12 -0400 (EDT)

Jason: An energy solution alone most probably will not suffice... Your example
would probably require an energy-momentum solution such as that derived by
Glennon Loumiet (see the Accident Reconstruction Journal).. such algorithms are
at the root of most software (SLAM Edcrash etc.) used for the purpose. X and Y
energies as described by you could only be used to determine the total energy
dissipated in damage. The energy magnitudes alone cannot even reveal which car
might have been stationary (if either)! The amount of damage observed on one of
two vehicles involved in a crash has no bearing on the speed of that particular
vehicle when isolated. The damages observed on both vehicles alone cannot predict
which vehicle was traveling faster or the speeds of each vehicle independently.
One prevalent misconception is that the vehicle with the most damage was traveling
the fastest... not so! THE SOFTER CAR WILL SUSTAIN THE MOST DAMAGE! The proper
algorithm will require many inputs including locations of impact area final
rest positions of the cars stiffness coefficients for both vehicles Principle
Directions of Force vehicular weights pre-impact steering descriptions
post-impact surface frictions... etc.

Such complexity is the reason that a simple momentum solution is preferable
(360-degree or right-angle solutions). Hope this helps. Ed Livesay
Ed Livesay
EdLivesay@worldnet.att.net

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