The objective of this work is to characterize the human head dynamic response under shock conditions by a new 3D finite element model and to transfer the results to a physical model intended for "measuring" the shock severity.

The proposed3D FEM distinguishes the different anatomical features of the cerebral matter. Model validation is based on it's theoretical modal analysis compared to the in vivo mechanical impedance recordings of the head. Modal analysis of the model shows three vibration modes. The mode shapes are illustrated by brain rotations around the Z1, Y1-Y’1 and X1 axis respectively making an angle of n/8 rad with the and X reference axis.

The new proposed physical head model thus has an internal mass modeling the cerebral mass. The modelising of the mechanical liaisons between the brain and skull was achieved by visco-elastic liaisons. The adjustable elastic component permits 3 degrees of freedom relative to the brain-skull movement (two X, Y translations and the rotation around 2). The resonance frequencies of these three degrees of freedom were fixed by the theoretical modal analysis of the 3D finite element model

This new head models are especially suitable for distinguishing the risk of focal lesion or sub-dural haematoma from diffuse axonal injury risks.