EFFECT OF CEREBROSPINAL FLUID MODELED WITH DIFFERENT MATERIAL PROPERTIES ON A HUMAN FINITE ELEMENT HEAD MODEL

Abstract

The aim of this study was to enhance head-injury prediction, this paper investigated the behavior of cerebrospinal fluid (CSF) in finite element (FE) modeling. Nine different material properties selected according to material definitions and property values were used to represent CSF in FE head models. To evaluate the influence of CSF material parameters on brain mechanical responses, the models were validated against available cadaver experiment data. Results showed that coup pressure increased whereas contrecoup pressure decreased when the head sustained purely translational impact with increased bulk modulus when CSF was modeled as fluid. However, with increased bulk modulus, coup pressure, contrecoup pressure and relative skull-brain motions decreased under rotational impact. When CSF was assumed to be an elastic material, coup pressure increased whereas contrecoup pressure decreased with increased elastic modulus when the head was subjected to purely translational impact. However, the variation trend was not obvious during head rotation. Results also indicated that when subjected to brain strain and von Mises stress, the model was prone to underestimate brain injury when CSF was modeled as an elastic material, especially during purely translational impact to the head. The model with CSF as fluid reduced the strain rate of brain, which was more likely to be realistic than the model with CSF as a viscoelastic material. These findings suggested that significantly higher values of the bulk modulus of CSF modeled as fluid were needed to predict intracranial dynamic responses and brain injury during head impact.