Material modeling of the head’s subarachnoid space

The goal of this study is to investigate the mechanotransduction of an external load to the brain and the causation of concussion and Traumatic Brain Injury (TBI). However, as one step toward this goal, in this paper, the investigation of the material model selection and material properties of the subarachnoid space (SAS) are presented. As the interface between the skull and the brain, the material modeling of SAS plays an important role in the analysis of damping and movement of the brain within the skull, leading to TBI. Based on the histology and morphology of the SAS region, three material types, namely, soft solid, viscous fluid and porous media were proposed. To validate these material models, the relative displacement between the skull and the brain was compared with the experimental study. It was concluded that the optimum material properties of the three material models are for soft solid material, E=1000Pa, for viscous fluid, μ=0.25Pa.s, and for porous media, the permeability of 3.125×10−10 m2. The results indicated that the properties determined in this study for the three material models are appropriate and reliable for future investigations. That is, if one decides to use any of these materials to model the SAS, in local or global FE analyses, these values are suitable.