Analysis of motion of the body of a motor car hit on its side by another passenger car

Abstract

Based on an analysis of the course of a few experimental crash tests, a physical model and afterwards a mathematical model were prepared to describe the motion of bodies of the vehicles involved during the phase of impact. The motion was analysed in a global coordinate system attached to the road surface. Local coordinate systems were also adopted with their origins being placed at the centres of mass of the vehicles. Equations of motion of the model were derived. The calculation results enabled defining the influence of the location of the point of impact against the vehicle side on e.g. the following:- time history of the impact force exerted by the impacting car (A) on the impacted car (B) as well as characteristic values of this force and of the impulse of the impact force;- time histories showing changes in the velocity of the centre of vehicle mass and in the angle of deviation of the velocity vector from the direction of motion of the impacted vehicle before the collision;- trajectory of the centre of mass and angle of rotation of the body of the impacted vehicle. The calculations were focused on the initial period of motion of the body of the impacted vehicle, up to the instant of 200 ms from the start of the collision process. After this time, the vehicles separate from each other and move independently. The results obtained from the calculations covering this initial period make it possible to determine the starting-point values of the parameters to be taken for further calculations of the free post-impact motion of the cars.