Traumatic brain injuries from head impact are a major issue across areas such as defence, automotive and sports, and can be costly to research using experimental testing. These injuries can be explored, though, through 3D models created from scan data and computer simulations. Simpleware has worked with the US Naval Research Laboratory to develop a cutting-edge human head model suitable for a wide range of head injury simulations. Major innovations of the modelling workflow include the ability to generate multiple meshes from the same pre-segmented data (rather than fixed meshes), and the level of detail and flexibility possible for adding new parts and integrating CAD with image data.
Cotton et al., 2015. Development of a geometrically accurate and adaptable finite element head model for impact simulation: the Naval Research Laboratory-Simpleware Head Model. Comput Meth Biomech Biomed Eng, [in press].
Pearce, C., Young, P., 2015. On the Pressure Response in the Brain Due to Short Duration Blunt Impacts. PLOS One, 9(12), e114292.
A high resolution in-vivo whole head MRI scan of a male volunteer was acquired at the Royal Devon and Exeter Hospital with a slice to slice separation of 1.04001 mm. The subject was 25 years old, 1.8m tall, and weighed 81 kg.
The data was imported to Simpleware ScanIP for segmentation, with a range of software tools used to identify multiple regions of interest, including skin, muscles, and soft tissue.
Simpleware CAD was employed to build additional regions, such as the facial and neck muscles, using voxelization methods. This method also allows helmets, pathologies and probes to be incorporated into image data.
Segmented image data can be converted into a multi-part mesh in Simpleware FE using two approaches – an EVOMAC-based approach (FE Grid) that converts voxels directly into finite elements, and more flexible surface triangulation followed by Delaunay tetrahedralization, producing unstructured, fully tet meshes that can be easily adapted (FE Free). Simpleware meshing also allows contacts, node sets and shells to be added, Boolean operations to be applied, and material properties to be assigned.
The NRL/Simpleware head model was generated as an unstructured tetrahedral mesh with 3.72 M volumetric elements using FE Free.