Development of realistic human head model
A new approach to generating physical and numerical models of the human head is presented. In this study, analytical, numerical and experimental models were used in parallel to explore the pressure response of the human head as a result of low velocity impact.
Characteristics:
- Based on in vivo patient data
- Segmentation tools to aid separation of multiple, interconnecting parts
- 15 structures segmented including hard and soft tissues
- Highly complex, robust, accurate mesh of multiple regions
- FE analysis performed directly on generated mesh using LS-Dyna
Thanks to
I Image Processing
A high resolution T1-weighted MRI scan of a healthy 26yr old male was obtained in vivo. 15 structures were segmented, including; brain (gray + white matter, brain stem, cerebellum), CSF, skull, mandible, cervical vertebrae, intervertebral discs, eye (eyeball, optic nerve, fatty tissue), nasal passage and skin. Semi-automated and manually driven segmentation tools enabled the complex, interlinked structures to be identified.
II Mesh Generation
A number of finite element meshes were produced directly from the segmentation. The meshing parameters were adjusted to produced models ranging in size from 2-10 million elements. Each had high element quality (max aspect ratio of 10), conforming interfaces between parts and coincident nodes and elements across boundaries. The exterior surface of the skin was used to define a contact surface.
III Simulation
The mesh was exported to LS-DYNA® (LSTC, Livermore, USA). An impactor was introduced with a velocity of 7m/s, a mass of 6.8kg and an event duration 15ms. The brain region was set as a viscoelastic material, the CSF as an elastic fluid and everything else was an elastic material. Pressure transients through the brain were observed, as were the Von Mises stresses produced in the intervertebral discs and cervical vertebrae. ►Videos
Model Tree to view/hide the layers of the model.
Head Impact Simulation: Stress
This animation shows the result of the LS-Dyna simulation in Oasys D3Plot. The mesh has been cut in the sagittal plane to show just the pressure transient in the brain. The pressure wave can be seen travelling across the brain as a result of the object impacting the head.
Head Impact Simulation: Movement
This animation shows the result of the LS-Dyna simulation in Oasys D3Plot. In this video, the outer skin part has been removed to show just the stresses in the neck vertebrae as a result of an object impacting the forehead.
Head Model: Layers disappearing
This video has been created from the rendering of the 3D model in ScanIP. It shows the various segmented parts of the head model from the MRI scan. The FE meshes were automatically created from this segmentation in +ScanFE.
