In silico investigation of intracranial blast mitigation with relevance to military traumatic brain injury

http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA533075&Location=U2&doc=GetTRDoc.pdf

In silico investigation of intracranial blast mitigation
with relevance to military traumatic brain injury

Michelle K. Nyeina, Amanda M. Jasona, Li Yua, Claudio M. Pitaa, John D. Joannopoulosb,
David F. Moorec, and Raul A. Radovitzkya



Blast-induced traumatic brain injury is the most prevalent military
injury in Iraq and Afghanistan, yet little is known about the mechanical
effects of blasts on the human head, and still less is known
about how personal protective equipment affects the brain’s
response to blasts. In this study we investigated the effect of the
Advanced Combat Helmet (ACH) and a conceptual face shield on
the propagation of stress waves within the brain tissue following
blast events. We used a sophisticated computational framework
for simulating coupled fluid–solid dynamic interactions and a
three-dimensional biofidelic finite element model of the human
head and intracranial contents combined with a detailed model
of the ACH and a conceptual face shield. Simulations were conducted
in which the unhelmeted head, head with helmet, and
head with helmet and face shield were exposed to a frontal blast
wave with incident overpressure of 10 atm. Direct transmission of
stress waves into the intracranial cavity was observed in the unprotected
head and head with helmet simulations. Compared to the
unhelmeted head, the head with helmet experienced slight mitigation
of intracranial stresses. This suggests that the existing ACH
does not significantly contribute to mitigating blast effects, but
does not worsen them either. By contrast, the helmet and face
shield combination impeded direct transmission of stress waves
to the face, resulting in a delay in the transmission of stresses
to the intracranial cavity and lower intracranial stresses. This
suggests a possible strategy for mitigating blast waves often associated
with military concussion