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- Boström, Ola, 1963, et al.
(author)
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Prediction of neck injuries in rear impacts based on accident data and simulations
- 1997
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In: PROCEEDINGS OF THE 1997 INTERNATIONAL IRCOBI CONFERENCE ON THE BIOMECHANICS OF IMPACT. ; , s. 251-264
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Conference paper (peer-reviewed)abstract
- Whiplash associated disorders, occurring in car accidents, are an increasing problem worldwide. According to real-life data from police records, the struck car's velocity change (delta V) and occupant gender are two of the most important factors related to Abbreviated Injury Scale (AIS) 1 neck injuries. In this study, a new rear-impact ranking of cars based on 4432 police reported accidents is presented. The ranking concerns the relative neck injury risk and compensates for the influences of car weight and gender. Moreover, some important factors influencing the risk of AIS 1 neck injury are proposed. These include: the stiffness, damping and yielding characteristics of the seat back, the muscle response of the occupant, and the delta V of the struck car and acceleration pulse. Using a mathematical model it is shown that the influence from these factors can be explained by a recently proposed neck injury criterion (NIC). This criterion is based on the neck motion at the passage of full neck retraction. The NIC, based on a number of volunteer tests, is analysed and validated. The consequence of injury outcome of an observed overall seat back stiffening is also discussed. In conclusion, for delta V below 20 km/h, real-life data show that the geometry of the head restraint is of minor importance. A seat back with low yielding limit or soft performance may be preferable. Moreover, the new NIC seems to be a good predictor of real-life neck injuries.
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| 2. |
- Krafft, Maria
(author)
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Non-fatal injuries to car occupants : injury assessment and analysis of impacts causing short- and long-term consequences with special reference to neck injuries
- 1998
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Doctoral thesis (other academic/artistic)abstract
- This thesis addresses non-fatal injuries leading to disability following motor vehicle collisions. The main focus is on minor (AIS 1) neck injuries, also called whiplash injuries. The purpose is to describe the distribution of disabilities among car occupants over time and to study the importance of different injury severity assessment levels on the priority ranking of the disability pattern. Another purpose is to study the characteristics and associated risk factors of rear impacts causing short- and long-term consequences to the neck (AIS 1) regarding crash severity and risk of injury in the struck car, in different car models. The materials used in the studies were data from insurance files, police reports and crash recordings of real-life rear impacts where the change of velocity and the crash pulse were measured. It was found that during the last two decades there has been a change in the distribution of disabilities. Two body regions dominated the change. Injuries to the lower extremities decreased since the 1970s and AIS 1 neck injuries increased. Furthermore, depending on level of disability, different types of injuries were predominant. For example, head injuries dominated higher disability levels were while for lower disability levels, neck injuries (AIS 1) followed by injuries to the extremities dominated. Concerning risk factors for AIS 1 neck injuries in rear impacts there were differences regarding crash severity parameters for long- and short-term consequences. Earlier studies have shown that the risk of initial symptoms to the neck are strongly related to the change of velocity. In this study it was found that, given initial symptoms, disability seemed to be more related to the acceleration of the struck car. It was also found that the relative disability risk was higher in cars manufactured at the end of 80s and beginning of the 90s than at the beginning of the 80s. Results from 22 Crash- Pulse-Recorders indicated that the shape of the pulse as well as the peak acceleration vary widely in real-life rear impacts. However, disability can occur when the change of velocity is at least 23 km/h and the peak acceleration 15 g. The principal conclusion is that AIS 1 neck injuries have increased both in proportion and in number and are the dominating injury among non-fatal injuries leading to disability. Better knowledge of risk factors causing disability is needed, especially the influence of crash severity measured as change of velocity and acceleration. This should preferably be evaluated with on-board measurement techniques in real-life collisions. In addition, it is recommended that the prevention of neck injuries in rear impacts should be directed toward the seat characteristics of the car. Also, priorities for intervention should be based on fatalities and injuries causing long-term consequences.
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