Combining Head Models with Composite Models to Simulate Ballistic Impacts

摘要

Numerical modelling of a helmeted head undergoing ballistic impact has been undertaken using a number of finite element codes and models. The University of Waterloo composite helmet model has been combined with a model of the human head, originally developed for automotive crash studies and extended to consider trauma due to ballistic impact. Two head models were considered. Initially, the Delegation Generale pour l'Armement (DGA) head model was run within the PAMCRASH finite element code. This choice of code and head model was adopted to enable collaborative exchange with the French DGA and required implementation of the Waterloo composite model within PAMCRASH. Incompatibilities were identified mid-way through the implementation process; however, modifications to PAMCRASH to allow proper treatment of the delamination algorithm have not been made available by ESI to date. As a work-around to the problems encountered in PAMCRASH, it was decided to run the simulations within VEC-DYNA. To facilitate this work, DGA has allowed the university to convert their head model to VEC-DYNA format. Once the conversion was completed, it has been possible to perform the required simulations and preliminary predictions of the contact forces resulting from the impact of the backplane with the skull have been obtained. At present, the existing head model requires further mesh refinement in the vicinity of the impact sites to accurately capture local contact conditions. There is also a need to migrate the delamination interface from VEC-DYNA to the proprietary version of LS-DYNA. The skull re-meshing task is underway in follow-on work in an internally funded project at Waterloo while a joint project with UBC under DREV funding will address the delamination interface implementation.