Multi-scale mechanics of traumatic brain injury

Despite the development of injury protection measures (such as belts, airbags, helmets), and an increase of governmental regulations, traffic accidents are responsible for a large number of traumatic brain injury (TBI) cases. Many of the hospitalised victims suffer from permanent disability with inherent high social cost. The relation between the mechanical load on the head and mechanical response of the brain is often investigated using numerical models (finite element models) of the head which contain a limited amount of detail of the anatomical substructure of the brain. During accidents, the mechanical impact on the head is translated into stresses and strains of the tissue of this brain substructure, leading to injury of the brain through the loss of functionality or death of cells at an even smaller length scale. A crucial step in understanding the mechanism by which TBI develops due to accidents is to translate the global head loads to the loading conditions, and consequently damage, of the cells at the local level and to project cell level and tissue level injury criteria towards the level of the head. This project will focus on bridging the various length scales that are involved in the mechanism of TBI development due to impact, such that the macroscopic mechanical loads are translated into mechanical loading of brain tissue and individual cells via the underlying microstructure of the brain at various levels. Multi-scale numerical techniques will be adapted for brain tissue, which has a rather complicated microstructure and is subjected to dynamic loading conditions. These techniques will be used to establish a link between various length scales by expanding the knowledge on the mechanics and injury development at the cellular level to the tissue level and to the global level of the complete head, where impact occurs and safety measures have to be taken.