Approximately 66% of all airbag deployments in the United States result in at least one skin injury, with 47% of these skin injuries attributed directly to the airbag deployment. In order to reduce this injury risk, the purpose of the study was to evaluate risk of skin abrasions from various airbag seam designs using a new shear methodology. The high-rate shear loading was performed with pneumatic impactor that propelled a section of airbag fabric across porcine skin at 85 m/s in order to simulate the interaction of the seam across the forearm during an airbag deployment. A total of 27 tests (3 control and 24 with fabric) were performed with 8 different seam designs. A 40 cm by 10 cm section of airbag fabric with each seam was forced across a 5 cm by 5 cm of porcine skin that was acquired within two hours post-mortem. A new skin injury scaling system, the total abrasion score, was created that quantifies the relative volume of skin removed by using cross-section histology slides to examine the depth and width of the abrasion for the entire sample. No abrasions were observed in the 3 control tests, but abrasions were observed in all 24 of the tests with airbag fabric. The abrasions ranged from minor removal of epidermal tissue to more severe abrasions into the subcutaneous level. The photographic images indicated that the tissue transfer occurred primarily on the seam portion of the fabric samples. Statistical analysis revealed that the unturned sewn seam orientation resulted in significantly more severe abrasions than the woven unturned seam orientation (p = 0.01). In addition, this system and results illustrate that shear loading should be considered in addition to normal loading, and that severe abrasions can be caused by normal pressures well below the 1.75 MPa injury threshold previously published.
Keywords:
Airbags; Arms; Face, Injury Criteria, Shear