Material characterization of subcutaneous adipose tissue and its application in traffic injury prevention

Obesity is a major public health issue that affects over one in three American adults annually, over 90 million adults total.1 Consequently, a major part of America populace is at a higher risk of death in motor vehicle crashes (MVCs), as obesity is considered a large co-morbidity factor during traffic accidents. 2 Kent et al. concluded obese occupants have an elevated risk of lower-body injury, as they experience greater hip movement. This results in a greater risk of impact with the car interior, increasing injury risk.2 Due to this risk, there is a need to better the modelling of obese occupants in MVCs. Thus, we aimed to produce a model of adipose tissue, a factor that distinguishes obese individuals, as obese individuals have excess adipose tissue. Modelling the behavior of adipose tissue at high strain and strain rate would increase the accuracy of computational crash models. Shear and compression are two loading modes adipose tissue experiences during MVCs. Since adipose tissue is soft, it required design of a custom testing device that was able to expose the material to shear and compression without damaging the specimen between modes. After development of a testing system, we performed a pilot study and identified a strong non-linear behavior and viscoelastic nature of adipose tissue. This analysis drew strong attention from the automotive industry, as current models do not represent obese occupants well. Inclusion of updated adipose tissue data would allow us to simulate more passengers, beyond the standard 50th percentile male current model. 1. https://www.cdc.gov/obesity/data/adult.html 2. Kent, Richard W., et al. “Is There Really a ‘Cushion Effect’?: A Biomechanical Investigation of Crash Injury Mechanisms in the Obese.” Obesity, vol. 18, no. 4, 2009, pp. 749–753., doi:10.1038/oby.2009.315.