The effects of different brain material properties, FE mesh size and hourglass modes on the results of FE head impact analyses

摘要

Finite element head models arc used to obtain a better insight in the mechanisms of head injuries. Current FE head models have a detailed geometrical description of the anatomical components of the head but often lack accurate descriptions of the brain material behavior and the contact between the brain and the cerebrospinal fluid. Also more attention should be paid to the FE mesh size and the hourglass modes which can arise when a reduced integration method is used to calculate the displacement field within the finite elements. These hourglass modes, also called zero energy modes, should be eliminated such that they can not invalidate the results. This paper therefore starts with the development of a generic simplified head model to investigate the influence of the brain material properties, the FE mesh size and the hourglass modes on the results of an impact analysis. From the performed study it follows that during a FE analysis with reduced integration elements, hourglass modes need to be eliminated to obtain correct, reliable results. The study also highlights the need for a more accurate description of the brain material properties for predicting head injuries because these properties have a large influence on the biomechanics of brain behavior.