Brain strains in vehicle impact tests.

The purpose of this research was to use vehicle impact test data and parametric finite element analysis to study the contribution of translational accelerations (TransAcc) and rotational accelerations (RotAcc) on strain-induced head injuries. Acceleration data were extracted from 33 non-contact vehicle crash tests conducted by the US Department of Transportation, National Highway Traffic Safety Administration. A human finite element head model was exercised using head accelerations from the nine accelerometer package placed inside the driver dummy in these tests. Three scenarios were parameterized: both TransAcc and RotAcc, only TransAcc, and only RotAcc to demonstrate the contribution of these accelerations on brain injury. Brain strains at multiple elements, cumulative strain damage, dilatation damage, and relative motion damage data were compared. Rotational accelerations contributed to more than 80% of the brain strain. Other injury metrics also supported this finding. These findings did not depend on the crash mode, peak amplitude of translational acceleration (29 to 120 g), peak amplitude of rotational acceleration (1.3 to 9.4 krad/s ( 2 ) ) or HIC (68-778). Rotational accelerations appeared to be the major cause of strain-induced brain injury.