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An Impact Moment Coefficient for Vehicle Collision Analysis
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English
Abstract
Many investigators have used the equations of impulse, momentum and energy to analyze the changes in velocities when two vehicles collide. The equations generally include the classical coefficient of restitution which is used as a measure of energy loss. These equations and the coefficient are based upon large forces and short-duration contact between the two bodies. In all real collisions contact is over a surface, and in many vehicle collisions, momentary or permanent interlocking of deformed parts occurs over this surface. This causes a moment to develop whose impulse can significantly affect the dynamics; most authors neglect or ignore this moment (1, 2, 3, 4, 5)*. In this paper, the equations of impact of two vehicles are derived including the moment impulse. An impact moment coefficient is defined. The value of this coefficient determines the extent to which a moment is developed between the two vehicles during impact. Two examples are presented. The first is a simple classical problem of two rigid bodies impacting over a common surface and is presented to illustrate the concept of the impact moment coefficient. The second example uses data from an actual collision of two automobiles and shows that in accident reconstruction problems, an a priori value of the impact moment coefficient is often not needed.
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Authors
Citation
Brach, R., "An Impact Moment Coefficient for Vehicle Collision Analysis," SAE Technical Paper 770014, 1977, https://doi.org/10.4271/770014.Also In
References
- Rosenthal F. et. al. “The Mechanics of Automobile Collisions” NRL Memorandum Report 2417 May 1972
- Jones Ian “Mechanics of Roll Over as the Result of Curb Impact,” SAE 750461 Feb. 1975
- Wilson James F. “Two-Vehicle Collision Reconstruction: A Rational, Computer Aided Approach,” Vehicle System Dynamics 2 1973 205 223
- Neilson I.D. “The Theoretical Reconstruction of Events Leading to an Impact in a Road Accident,” TRRL Report LR 575 Transportation and Road Research Laboratory Crowthorne, Berkshire, Engl. 1973
- Grime G. Jones I.S. “Car Collisions - The Movement of Cars and Their Occupants in Accidents,” Proc. Instn. Mech. Engrs. 184 5 1969-70
- McHenry Raymond R. “A Computer Program for Reconstruction of Highway Accidents,” Proceedings of the 17th Stapp Car Crash Conference 1973
- Sachs Herbert K. “On a One-Dimensional Model of Vehicle Crashworthiness,” Israel Journal of Technology 12 1974 138 144
- Timoshenko S. Young D.H. Advanced Dynamics” McGraw Hill N.Y. 1948 133
- Goodman L.E. Warner W.H. “Statics and Dynamics” Wadsworth Belmont, Calif. 1964
- Goldsmith W. “Impact” Edward Arnold London 1960
- Horak Z. “Impact of a Rough Ball Spinning Round Its Vertical Diameter onto a Horizontal Plane,” 1 1948 1
- Ellis J.R. “Vehicle Dynamics” Business Books Ltd. London 1969
- Brach R.M. “Friction and the Mechanics of Skidding Automobiles,” Highway Research Record 376 Transportation Research Board, NRC 1971