| Popis: |
The purpose of this paper is to make an assessment on the performance of an FRP helmet-head system subjected to ballistic impact. Firstly, an FE model for human head is developed in which it mainly consists of scalp, skull, meanings, cerebrospinal fluid, brain tissue, falx, tentorium, face and neck. Constitutive models for each component of the head are determined and, in particular, strain rate effects of the compact bone of skull and the hyperelastic property of scalp are taken into account for the first time. Secondly, an FE model for Kevlar fibre reinforced phenolic helmet are constructed based on PASGT helmet. Recently developed dynamic constitutive models for metals and FRP laminates are employed for FMJ bullet and the KFRP helmet, respectively in the present study. Finally, both the head and helmet models are validated against available test data. Furthermore, effects of padding system (strap-netting and OA foam), impact position (top, front, lateral and rear), and projectile type (FSP and FMJ) on the ballistic performance of the helmet-head system have been systematically investigated with special attention being paid to the severity of head injury. It is found that the performance of the helmet with OA foam is advantageous over that of the helmet with strap-netting in head injury prevention; that the most harmful impact positions are different for helmets with different liner systems. It is also found that a lower velocity (358m/s) FMJ bullet pose more threats to head injury than a higher velocity (610m/s) FSP for the PASGT helmet-head system. |
