Motion state recognition of debris ejected in vehicular collision after contact with the ground

The motion state of debris ejected from the vehicle involved in vehicular collision is important for finding out the vehicle collision speed. This research developed an analytical model to recognise the debris motion state. With the model, analyses were conducted, which reveal that if α, which is the contact angle between the debris and the ground at the moment when the debris collides the ground, is within the range from 0° to its boundary value, then the debris slides; if α is within the range from its boundary value to 90°, then the debris bounces. With debris' initial angular velocity ω = 0, the boundary value is 11.8° for sphere debris and 7.8° for rectangular debris; with ω ≠ 0, the boundary value for rectangular debris is arcsin(g / Rω2) where g represents the acceleration due to gravity and R is the distance from the debris centre to the point of its contact with the ground. Experiment tests were conducted for debris motion states with ω = 0, which confirmed the analytical results.