Citation

Gabler LF, Joodaki H, Crandall JR, Panzer MB. J. Biomech. Eng. 2018; 140(3): e4038357.

Affiliation

4040 Lewis and Clark Drive Charlottesville, VA 22903.

Copyright

(Copyright © 2018, American Society of Mechanical Engineers)

DOI

10.1115/1.4038357

PMID

29114772

Abstract

Linking head impact kinematics to injury risk has been the focus of numerous brain injury criteria. Although many early forms were developed using mechanics principles, recent criteria have been developed using empirical methods based on subsets of head impact data. In this study, a single-degree-of-freedom (sDOF) mechanical analogue was developed to study the link between rotational head kinematics and brain deformation. Model efficacy was assessed by comparing its dynamic response to strain-based brain injury predictors from finite element (FE) human head models. A series of idealized rotational pulses covering a broad range of acceleration and velocity magnitudes (0.1-15krad/s2 and 1-100rad/s) with durations between (1-3000ms) were applied to the mechanical models about each axis of the head.

RESULTS show that brain deformation magnitude is governed by three categories of rotational head motion each distinguished by impact duration relative to the brain's natural period: for short-duration pulses, maximum brain deformation depended primarily on angular velocity magnitude; for long-duration pulses, brain deformation depended primarily on angular acceleration magnitude; and for pulses relatively close to the natural period, brain deformation depended on both velocity and acceleration magnitudes. These results suggest that brain deformation mechanics can be adequately explained by simple mechanical systems, since FE model responses and experimental brain injury tolerances exhibited similar patterns to the sDOF model. Finally, the sDOF model was the best correlate to strain-based responses, and highlighted fundamental limitations with existing rotational brain injury metrics.

Language: en