Studies conducted by the University of Pennsylvania have shown that subdural hematoma, diffuse axonal and other shearing type brain injuries are the most common causes of death and disability seen in human head injury, and that angular acceleration is the primary cause. It is, therefore, the main interest of this paper to study and relate the coronal or angular acceleration-induced shear strain that is exerted on the brain and its connective tissue to the tolerance, or threshold of the above mentioned head injuries.

In this study, the human head is modelled as a 3-degrees-of-freedom mechanical system using a lumped parameter approach. The model consists of masses, springs and dampers and has been validated with experimental data obtained by the University of Pennsylvania.

The model was exercised with various loading conditions commonly seen in car crash environments. In addition, the effect of helmet and airbag on rotational head injury were investigated. The resulting dynamic responses of the model were utilized for computing the shearing strain and providing a way to establish some injury criteria for estimating the potential of rotational head injury in actual car crash simulation.