A curtain airbag (CAB) plays a significant role in not only protecting an occupant head from side impact crashes, but also preventing an occupant being partially or totally ejected during rollover accidents. As the seriousness of rollover accident has been statistically studied and reported, the latter function of CAB become more emphasized than before. At last, NHTSA released FMVSS226 final rule in January 2011 which limits the linear travel of impactor headform by 100mm.

This paper focuses on how to meet the requirement by enhancing CAB design and on establishing design guideline through its parametric study. For this, 9 design factors are selected which have major effect on ejection mitigation performance and the effectiveness of each factor is analyzed. They are cushion pressure, amount of coating, cushion shape, cushion depth, overlapping area between door trim and cushion, strength of cushion mounting tab and tether, location of front tether and lastly, distance between impact target point (A3) and cushion mounting.

From this study, the parametric guideline of CAB design factors for satisfying the required excursion limit of 100mm is found out and the test result with the CAB module applied these parameter level shows that the goal is successfully achieved within the excursion of 80mm in all target locations with the test speed of 24kph in accordance with NPRM. At last part, the future work to optimize this for smaller glazing is mentioned.