A comprehensive experimental study on material properties of human brain tissue.

A comprehensive study on the biomechanical response of human brain tissue is necessary to investigate traumatic brain injury mechanisms. Published brain material property studies have been mostly performed under a specific type of loading, which is insufficient to develop accurate brain tissue constitutive equations. In addition, inconsistent or contradictory data in the literature made it impossible for computational model developers to create a single brain material model that can fit most, if not all, experimental results. In the current study, a total of 240 brain tissue specimens were tested under tension (n=72), compression (n=72), and shear (n=96) loading modes at varying strain rates. Gray-white matter difference, regional difference, and directional difference within white matter were also investigated. Stress-strain relationships of human brain tissue were obtained up to 50% of engineering strain. Strain rate dependency was observed under all three loading modes. White matter was stiffer than gray matter in compression and shear. Corona radiata was found to be stiffer than cortex, thalamus, and corpus callosum in tension and compression. Directional dependency of white matter was observed under shear loading.