Modeling of a Sliding Phase in Accident Reconstruction

Wieslaw M. Szydlowski; P. E. Jenkins

doi:10.4271/930655

1993-03-01

Modeling of a Sliding Phase in Accident Reconstruction 930655

In road accidents involving pedestrians, the speed of a vehicle is determined from the distance covered by the thrown body. The distance under consideration includes both flight and sliding and is known as a throw length.

This paper describes an attempt to develop an improved model of a sliding phase. The pedestrian is treated as a moving mass supported by a spring and a dashpot. The friction present between the body and the ground depends on the sliding velocity of the mass. The use of the spring and non-linear dashpot allows for better modeling of the force between the body and the ground, and more accurate computation of the length of the sliding phase.

The developed model and a procedure for computing the length of the airborne trajectory were incorporated in a computer program to predict the throw distances for simulated accidents.

The results of computations for a new model are in good agreement with the data obtained from the real accidents.

The developed model has also been used to simulate the tumble number proposed by T.A. Bratten. The results of the simulation seem to confirm the existence of the tumble number at least for the selected category of accidents:impacts with a “high”-fronted vehicles at velocities from 10 to 16 m/s.

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Modeling of a Sliding Phase in Accident Reconstruction 930655

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