The validation of the Strasbourg University (France) "ULP" finite element (FE) head model has been extended to include five tests by X. Trosseille and two tests by N. Yoganandan. Only one of each, however, is reported in this paper. Results show that the model correlated well with X. Trosseille's experiments and predicted the intracranial pressure accurately at sites near to the impact location; predictions became less accurate as the distance from the impact location increased. The skull stiffness and fracture force were very accurately predicted when compared with values measured by N. Yoganandan. The model was studied parametrically to give a better understanding of how the output varied for different values of the material characteristics such as cerebral spinal fluid (CSF) Young modulus, brain short and long term shear modulus, brain Bulk modulus, and skull thickness. Helmet damage from thirteen motorcycle accidents selected from the COST 327 Action database was replicated in drop tests at Transport Research Laboratory (TRL, UK). Simulation of these accidents using the ULP FEM produced very first tentative proposals for injury criteria as follows: intracerebral Von Mises stress of about 20 kPa for concussion, strain energy in the CSF layer of 4J for subdural haematoma, and a Tsai-Wu criterion for skull fracture. (A)
Abstract