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Optimizing Seat Belt and Airbag Designs for Rear Seat Occupant Protection in Frontal Crashes
Published November 13, 2017 by The Stapp Association in United States
This content contains downloadable datasetsAnnotation ability available
Recent field data have shown that the occupant protection in vehicle rear seats failed to keep pace with advances in the front seats likely due to the lack of advanced safety technologies. The objective of this study was to optimize advanced restraint systems for protecting rear seat occupants with a range of body sizes under different frontal crash pulses. Three series of sled tests (baseline tests, advanced restraint trial tests, and final tests), MADYMO model validations against a subset of the sled tests, and design optimizations using the validated models were conducted to investigate rear seat occupant protection with 4 Anthropomorphic Test Devices (ATDs) and 2 crash pulses. The sled tests and computer simulations were conducted with a variety of restraint systems including the baseline rear-seat 3-point belt, 3-point belts with a pre-tensioner, load limiter, dynamic locking tongue, 4-point belts, inflatable belts, Bag in Roof (BiR) concept, and Self Conforming Rear seat Air Bag (SCaRAB) concept. The results of the first two sled series demonstrated that the baseline 3-point belt system are associated with many injury measures exceeding injury assessment reference values (IARVs); showed the significance of crash pulse and occupant size in predicting injury risks; and verified the potential need of advanced restraint features for better protecting the rear-seat occupants. Good correlations between the tests and simulations were achieved through a combination of optimization and manual fine-tuning, as determined by a correlation method. Parametric simulations showed that optimized belt-only designs (3-point belt with pre-tensioner and load limiter) met all of the IARVs under the soft crash pulse but not the severe crash pulse, while the optimized belt and SCaRAB design met all the IARVs under both the soft and severe crash pulses. Two physical prototype restraint systems, namely an “advanced-belt only” design and an “advanced-belt and SCaRAB” design, were then tested in the final sled series. With the soft crash pulse, both advanced restraint systems were able to reduce all the injury measures below the IARVs for all four ATDs. Both advanced restraint systems also effectively reduced almost all the injury measures for all ATDs under the severe crash pulse, except for the THOR. The design with the advanced-belt and SCaRAB generally provided lower injury measures than those using the advanced belt-only design. This study highlighted the potential benefit of using advanced seatbelt and airbag systems for rear-seat occupant protection in frontal crashes.
CitationHu, J., Reed, M., Rupp, J., Fischer, K. et al., "Optimizing Seat Belt and Airbag Designs for Rear Seat Occupant Protection in Frontal Crashes," SAE Technical Paper 2017-22-0004, 2017, https://doi.org/10.4271/2017-22-0004.
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- Arbogast, K.B., Maltese, M.R., Locey, C., Bohman, K., 2012. Headform Impact Tests to Assess Energy Management of Seat Back Contact Points Associated with Head Injury for Pediatric Occupants. SAE International Journal of Passenger Cars - Mechanical System 5, SAE2012-2001-0561.
- Bilston, L.E., Du, W., Brown, J., 2010. A matched- cohort analysis of belted front and rear seat occupants in newer and older model vehicles shows that gains in front occupant safety have outpaced gains for rear seat occupants. Accid Anal Prev 42, 1974-1977.
- Digges, K., Dalmotas, D., Prasad, P., 2013. An NCAP star rating system for older occupants, The 23rd International Technical Conference on the Enhanced Safety of Vehicles (ESV), Seoul, Republic of Korea.
- Forman, J., Lopez-Valdes, F., Lessley, D., Kindig, M., Kent, R., Ridella, S., Bostrom, O., 2009. Rear seat occupant safety: an investigation of a progressive force-limiting, pretensioning 3-point belt system using adult PMHS in frontal sled tests. Stapp Car Crash Journal 53, 49-74.
- Forman, J., Michaelson, J., Kent, R., Kuppa, S., Bostrom, O., 2008. Occupant restraint in the rear seat: ATD responses to standard and pre- tensioning, force-limiting belt restraints. Annals of Advances in Automotive Medicine 52, 141-154.
- Hu, J., Fischer, K., Lange, P., Adler, A., 2015. Effects of Crash Pulse, Impact Angle, Occupant Size, Front Seat Location, and Restraint System on Rear Seat Occupant Protection. SAE 2015 World Congress SAE-2015-01-1453.
- Hu, J., Klinich, K.D., Reed, M.P., Kokkolaras, M., Rupp, J.D., 2012a. Development and validation of a modified Hybrid-III six-year-old dummy model for simulating submarining in motor-vehicle crashes. Medical Engineering & Physics 34, 541- 551.
- Hu, J., Reed, M., Klinich, K., 2012b. Characterizing Child Head Motions Relative to Vehicle Rear Seat Compartment in Motor Vehicle Crashes. UMTRI Technical Report UMTRI-2012-20.
- Hu, J., Wu, J., Klinich, K.D., Reed, M.P., Rupp, J.D., Cao, L., 2013a. Optimizing the rear seat environment for older children, adults, and infants. Traffic Inj Prev 14 Suppl, S13-S22.
- Hu, J., Wu, J., Reed, M.P., Klinich, K.D., Cao, L., 2013b. Rear seat restraint system optimization for older children in frontal crashes. Traffic Inj Prev 14, 614-622.
- Insurance Institute for Highway Safety, 2012. Dummy Seating Procedure for Rear Outboard Positions (Version I). www.iihs.org.
- Kent, R., Forman, J., Parent, D.P., Kuppa, S., 2007. Rear seat occupant protection in frontal crashes and its feasibility, The 20th International Technical Conference on the Enhanced Safety of Vehicles Conference Lyon, France.
- Kübler, L., Gargallo, S., Elsäßer, K., 2008. Characterization and evaluation of frontal crash pulses with respect to occupant safety, Airbag 2008 – 9th International Symposium and Exhibition on Sophisticated Car Occupant Safety Systems.
- Kuppa, S., Saunders, J., Fessahaie, O., 2005. Rear seat occupant protection in frontal crashes, The 19th International Technical Conference on the Enhanced Safety of Vehicles Washington D.C., USA.
- Mertz, H.J., Irwin, A.L., Prasad, P., 2003. Biomechanical and scaling bases for frontal and side impact injury assessment reference values. Stapp Car Crash Journal 47, 155-188.
- Prasad, A., Weston, D., 2011. NHTSA's Rear Seat Safety Research, The 22nd International Technical Conference on the Enhanced Safety of Vehicles, Washington D.C.
- Prasad, P., Mertz, H.J., Dalmotas, D.J., Augenstein, J.S., Diggs, K., 2010. Evaluation of the field relevance of several injury risk functions. Stapp Car Crash Journal 54, 49-72.
- Sahraei, E., Soudbakhsh, D., Digges, K., 2009. Protection of rear seat occupants in frontal crashes, controlling for occupant and crash characteristics. Stapp Car Crash Journal 53, 75-91.
- Smith, K.M., Cummings, P., 2006. Passenger seating position and the risk of passenger death in traffic crashes: a matched cohort study. Injury Prevention 12, 83-86.
- Takhounts, E.G., Craig, M.J., Moorhouse, K., McFadden, J., Hasija, V., 2013. Development of brain injury criteria (BrIC). Stapp Car Crash Journal 57, 243-266.
- Wu, J., Hu, J., Reed, M., Klinich, K., Cao, L., 2012. Development and Validation of a Parametric Child Anthropomorphic Test Device Model Representing 6- to 12-Year-Old Children. International Journal of Crashworthiness 17, 606-620.
- Zellmer, H., Luhrs, S., Bruggemann, K., 1998. Optimized restraint systems for rear seat passengers, The 16th International Technical Conference on the Enhanced Safety of Vehicles Windsor, Ontario, Canada.