Abstract
The study starts off by examining the various types of injuries caused to bus passengers involved in accidental impacts against road restraint systems.
The impact behaviour were reported and analysed by means of a computer and finite element software with a dummy designed for this purpose. Some real crash tests were also carried out in order to assess the interaction between the bus and barrier.
After the authors identified the correspondence of the real case to the virtual one, a computational mechanics study was carried out. It was determined that the two types of interaction, i.e. car-barrier and bus-barrier, are completely different.
When a car crashes, the passengers position is subject to mainly longitudinal and lateral forces; consequently, their bodies are prevalently thrown either in a longitudinal or transverse direction.
In the case of a bus crash, the occupants are subjected to accelerating forces with different directions and intensities.
During the deceleration phase the heavier part of the body, the trunk, is subjected to a forward thrust, while the head and neck undergo an extension movement, causing a load on the second cervical vertebra. These dynamics result in the chin impacting against the rear of the seat in front. Therefore this violent movement causes injuries to the capsular-ligamentous and bone structures of the cervical column which, if the impact is significant, are likely to be associated with vascular injuries caused by the pulling of the epiaortic vessels.
The conclusions to be derived are that it is important to use seatbelts, shoulder belts in particular, and that it is essential for passive road restraint systems to be deformable and equipped with sophisticated energy absorbers.