A cooperative research project with the National Highway Traffic Safety Administration (NHTSA) was conducted to evaluate the capability of a Tubular Thoracic Cushion (TTC) airbag concept to significantly reduce rib deflections for the SID-IIs dummy in the Insurance Institute for Highway Safety’s (IIHS) side-impact barrier test.

The concept of the TTC airbag was to efficiently distribute a majority of the crash force to the pelvis, which is more able to tolerate forces from side-impact crashes. The characteristic of the airbag to develop tension when deployed appeared to offer additional opportunities for occupant restraint in the IIHS side-impact environment.

Computer analysis confirmed that an approach of interposing an inflatable cushion between vehicle occupants at the ribs and a vehicle’s intruding side structure may be problematic when attempting to limit rib deflection, particularly for small-stature occupants.

NHTSA analysis of NCAP side-impact tests suggested that pelvic lead (pelvic loading prior to the loading of the rib cage) lessens severity of thoracic injury [1]. Simulations of the IIHS side-impact barrier test utilizing this approach of pelvic lead with the TTC device showed reductions in rib deflection to a 5th percentile female dummy when airbag inflation was limited only to the pelvis region.

Due to the characteristic of the TTC airbag to develop tension when deployed, a strategy of applying an inboard lateral "pre" load to the pelvis region of the SID-IIs dummy prior to intrusion was developed. This further reduced rib deflection in dynamic simulations and was validated in dynamic sled testing. The tensioning characteristic of the TTC airbag concept demonstrated pre-loading the pelvis of an occupant in the IIHS side-impact environment provided significant reduction in injury risk.