The Impact Response of Cranial Bone

Linear and depressed skull fractures are frequent mechanisms of head injury and are often associated with traumatic brain injury. Accurate knowledge and understanding of the fracture of cranial bone can provide insight into the prevention of skull fracture injuries and associated lesions of soft neural tissue and help aid the design of energy absorbing head protection systems. Cranial bone is a complex material comprising of a three-layered structure: external layers consisting of compact, high-density cortical bone and a central layer consisting of a low-density, irregularly porous structure. In the current study, a significantly large set of cranial bone specimens (parietal and frontal bones) were extracted from 8 crania and, after μCT imaging, the specimens were tested in a three-point bend set-up at dynamic speeds. Important mechanical and morphological properties were calculated for each specimen. The mechanical properties were consistent with those previously reported in the literature. Potential correlations between the calculated parameters were examined statistically. Testing speed, strain rate, cranial sampling position and intercranial variation were found to have a significant effect on some or all of the computed mechanical parameters. In addition, structurally detailed 3D finite element (FE) models were developed from the μCT data and validation and verification of these models is in progress with a view to improving the skull material and failure definitions in the UCD 3D-FE model of the skull-brain complex, currently used to aid helmet design. 1 This paper has not been peerreviewed and should not be referenced in open literature.