A Methodology for Measurement and Analysis of Head-To- B-Pillar Contact Pressure and Area Response 2001-01-0718

Government accident statistics show that approximately 35% of all car accident victims suffer an injury to the head and face. Such injuries are common during frontal, side, and rollover accidents as the head may impact the steering wheel, side pillars, windshield, or roof. Further, non-threatening injuries (i.e abrasions) may be suffered due to contact with the deployed airbag, or, in the case of an out-of-position occupant, a deploying airbag. While the forces and accelerations measured internal to the head are known to correlate with serious head injury (i.e. concussion, skull fracture, diffuse axonal injury), it is currently not possible to record how the loads are distributed over the head and face with the current ATD. Ultimately, such data could eventually be used to provide improved resolution as to the probability of superficial, soft tissue damage since past cadaver studies show that the distribution of contact pressures are related to such injuries. In the current study, we present a methodology to record the contact pressures and area between a Hybrid III, ATD head-neck complex and the B-pillar. This contact event represented one exemplar impact event, which typically results in soft tissue damage in the field. The ATD head /neck subassembly was mounted transversely on a carriage and propelled along a track to a given pre-impact velocity and was stopped by a rigid mounted B-pillar structure. The head/neck was propelled to three different velocities prior to impact: 7.9, 12.1 and 14.3 kph. The contact pressure and area at the interface of the head were recorded digitally using an electronic pressure transducer both with and without a side air curtain. At each impact velocity, the air curtain was statically inflated to pressures of 13.8, 20.7, 27.6, 41.4 & 55.1 kPa to determine the effect of bag pressure on head-pillar contact mechanics. The pressure mat transducer recorded the contact pressure and area at 1,340 Hz. It was found that direct contact of the head against the B-pillar produced large contact pressures centered at the point of contact which migrated as the head rotated laterally during the contact event. The introduction of the side air curtain produced a significant reduction in contact pressures and head g forces. These data show one method of determining how the head surface is loaded over time, and how that load is distributed over the head.