Face shield design against blast‐induced head injuries

Abstract

Blast-induced traumatic brain injury has been on the rise in recent years because of the increasing use of improvised explosive devices in conflict zones. Our study investigates the response of a helmeted human head subjected to a blast of 1 atm peak overpressure, for cases with and without a standard polycarbonate (PC) face shield and for face shields comprising of composite PC and aerogel materials and with lateral edge extension. The novel introduction of aerogel into the laminate face shield is explored and its wave-structure interaction mechanics and performance in blast mitigation is analysed. Our numerical results show that the face shield prevented direct exposure of the blast wave to the face and help delays the transmission of the blast to reduce the intracranial pressures (ICPs) at the parietal lobe. However, the blast wave can diffract and enter the midface region at the bottom and side edges of the face shield, resulting in traumatic brain injury. This suggests that the bottom and sides of the face shield are important regions to focus on to reduce wave ingress. The laminated PC/aerogel/PC face shield yielded higher peak positive and negative ICPs at the frontal lobe, than the original PC one. For the occipital and temporal brain regions, the laminated face shield performed better than the original. The composite face shield with extended edges reduced ICP at the temporal lobe but increases ICP significantly at the parietal lobe, which suggests that a greater coverage may not lead to better mitigating effects.

Protective Performance of Helmets and Goggles in Mitigating Brain Biomechanical Response to Primary Blast Exposure

“…Goggles act similar to a face shield or a visor. Several studies 31,33,36,39,43 have shown the excellent ability of face shields in mitigating the ICP. For example, Tse et al 43 studied the protective performance of single-layered and multi-layered face shields for frontal blast exposure.…”

“…Goggles act similar to a face shield or a visor. Several studies 31 , 33 , 36 , 39 , 43 have shown the excellent ability of face shields in mitigating the ICP. For example, Tse et al .…”

“…49 Most previous studies used the ICP, strain or strain rate as criteria to assess the bTBI. 12,18,20,36,37,39,43,50 Up to date, no studies have investigated the effect of protective equipment on CSF cavitation. Another limitation of the previous studies is the lack of detailed brain anatomy description in the human head model, which may affect the biomechanical responses of brain to blasts.…”

Ballistic Head Protection in the Light of Injury Criteria in the Case of the Wz.93 Combat Helmet

“…These categories vary depending on the duration of the impulse of force during which an injury is sustained, and the distance from the epicenter of an event. As pointed out [2,4,[6][7][8][9], traumas arising from blast impact are experienced within 3 to 100 microseconds of an event and, with a ballistic impact, within about 200 microseconds. In this case, high temperature is also an additional element of trauma.…”

Numerical Analysis of EOD Helmet under Blast Load Events Using Human Head Model

“…Tan et al [15] have developed a virtual model of finite elements of a human head and a helmet in order to help in the design of the next generations of helmets for ballistic and explosion protection. They carried out simulations of the head (with and without the helmet) under explosion using a Eurelian-Lagrangian approach and using the CoBi-FEM code to simulate the problem.…”