Friedman, K., Mattos, G., Bui, K., Hutchinson, J. et al., "Potential Effects of Deceleration Pulse Variations on Injury Measures Computed in Aircraft Seat HIC Analysis Testing," SAE Technical Paper 2017-01-2052, 2017.
Aircraft seating systems are evaluated utilizing a variety of impact conditions and selected injury measures. Injury measures like the Head Injury Criterion (HIC) are evaluated under standardized conditions using anthropomorphic dummies such as those outlined in 14 CFR part 25. An example test involves decelerating one or more rows of seats and allowing a lap-belted dummy to impact components in front of it, which typically include the seatback and its integrated features. Examples of head contact surfaces include video monitors, a wide range of seat back materials, and airbags. The HIC, and other injury measures such as Nij, can be calculated during such impacts. A minimum test pulse, with minimum allowable acceleration vs time boundaries, is defined as part of the regulations for a frontal impact. In this study the effects of variations in decelerations that meet the requirements are considered. A series of Finite Element simulations of a generalized aircraft seat were performed to determine the variation in HIC and Nij observed based on variations in the deceleration pulse. The results indicate that the pulse characteristics affect the resulting head motions and can influence the ability to pass the HIC analysis test.