Design of the Occupant Protection System for Critical Side Impact requirements

This paper describes the critical side impact requirements of overall global side regulations and the sensitivity of various side injury parameters on NCAP rating assessment. The federal side impact regulation FMVSS 214 made very stringent by adding oblique pole impact in addition to moving deformable barrier (MDB) test. Though the vehicle velocity is less in oblique pole test, the dynamic intrusions are more which causes severe injury for 5^th and 50^th %le occupants than MDB test. It was observed that typical injury parameter in side impact requirements is the thorax compression than other injuries, because it is very sensitive than Pelvic, Abdomen regions. To meet these critical injury requirements in side impact, the optimal side restraint system is mandatory in order to develop a safer vehicle with high NCAP score.

The side restraint system includes side airbags (thorax and curtain), Hip pusher block/foam padding, door trim arm rest, seat belts and seats. As mentioned, thorax compression is critical injury, thorax or pelvic thorax air bag and Hip pusher blocks are given much importance to protect the thorax region. Hip pusher block/ pelvic bolster is optimized such that it protects the pelvic area of different occupants ranges from 5^th and 50^th %le occupants. For better thorax protection, various sizes of thorax bags and its impact on thorax compression are studied. The single chamber thorax airbag is enlarged and its area is divided into two parts such that the bottom (Pelvic) chamber pushes the pelvic part in advance before thorax engages with door trim, and the top(Thorax) chamber provides cushioning effect for shoulder, such that thorax/rib cage will be protected in between under controlled deployment.