一份报告说，美国军方的先进战斗头盔（ACH）可能几乎无法保护士兵免受冲击引发的脑伤害。Raul Radovitzky及其同事使用一种精密的三维计算机模型研究爆炸激波如何穿过人头的颅骨、脑脊液以及柔软的脑组织。这组科学家发现，把空气压缩到正常的海平面压力的10倍的一次前方爆炸把能量通过面部、颅骨和软组织传入未受保护的头。这些模拟证明了美国军方的先进战斗头盔（ACH）在某种程度上延迟了这种冲击波到达头部，但是只能稍微减轻对脑的压力，因为大多数能量径直穿过面部。这些发现与此前的研究相矛盾，此前的研究提出这些头盔可能让冲击能量聚焦，并让先进战斗头盔（ACH）的佩戴者的脑伤害加剧。
冲击引发的外伤性脑伤害是在伊拉克和阿富汗的士兵遭受的最常见的伤害。这组作者建议说，配有优化的面罩的保护性头盔可能在未来更好地保护士兵免受冲击引起的外伤性脑伤害。（生物谷Bioon.com）
生物谷推荐英文摘要：
PNAS doi: 10.1073/pnas.1014786107
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,1, David F. Moorec, and Raul A. Radovitzkya,1
aInstitute for Soldier Nanotechnologies, Department of Aeronautics and Astronautics, Massachusetts Institute of Technology, Cambridge, MA 02139;
bInstitute for Soldier Nanotechnologies, Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139; and
cDefense and Veterans Brain Injury Center, Walter Reed Army Medical Center, Washington, DC 20307
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.
