Measurement of Brain Deformations in Human Surrogate Head under Impact Loading

Traumatic brain injury (TBI) is a major source of disability and mortality in road accidents. Several investigations proposed that head acceleration is one of the underlying injury mechanisms. However, the knowledge of acceleration-induced brain deformation in human or head surrogate is limited. The study aims to measure the full-field brain deformations in the surrogate head. Additionally, the role of stiff membranes, like falx and tentorium, was investigated. We mounted the human surrogate head on Hybrid-III neck and impacted with the velocity of 1, 3, and 5 m/s using a linear impactor system. The geometry of the 3D printed skin and skull of the human surrogate head is based on the geometry of the Global Human Body Model Consortium (GHBMC) head model. The interior of the skull was filled with gelatin to mimic the brain. The linear acceleration and rotational velocity about the center of mass of the head were recorded using a tri-axial accelerometer and angular rate sensor. Further, the brain deformations were recorded using a high-speed camera, and in-plane (2D) strains were estimated using digital image correlation (DIC). The linear acceleration of 65-435 m/s2, the angular velocity of 4-19 rad/s, and angular acceleration of 750-9533 rad/s2 was observed for the range of impact velocity considered. We estimated 0.2 to 0.6 normal and shear strains. This study demonstrates that the falx and tentorium affect the nearby strain field due to significant strain concentration. Overall, this work provides important insights into the biomechanics of brain deformation during impact loading.