Parametric study of effects of brain-skull boundary conditions and brain material properties on responses of simplified finite element brain model under angular acceleration impulse in sagittal plane

Abstract

In the present study, the effects of brain-skull boundary conditions on the responses of a simplified three-dimensional finite element model of a thin sagittal slice of the human head were investigated. The model was excited using a time-dependent angular velocity with a maximum of 16 rad/s (maximum angular acceleration, around 5000 rad/s2). The present study was conducted using the non-linear explicit finite element code LS-DYNA. Three methods for simulation of the brain-skull boundary conditions were investigated : 1) with brain rigidly attached to the skull; 2) using frictionless sliding contact allowing no separation between the brain and skull; and 3) direct simulation of cerebrospinal fluid CSF using a layer of eight-noded solid elements with fluid-like properties. Varying the method for simulation of the brain-skull boundary conditions appreciably affected the brain responses. However, varying parameters of a given method, such as viscosity of cerebrospinal fluid CSF and CSF-skull friction coefficient, exerted only minor effects on these responses. The present results suggest that accurate simulation of brain-skull boundary conditions requires direct representation of the subarachnoidal space/CSF as a fluid-like medium.