Factors Contributing to Increased Blast Overpressure Inside Modern Ballistic Helmets

Abstract

This study demonstrates the orientation and the "shape factor" have pronounced effects on the development of the localized pressure fields inside of the helmet. We used anatomically accurate headform to evaluate four modern combat helmets under blast loading conditions in the shock tube. The Advanced Combat Helmet (ACH) is used to capture the effect of the orientation on pressure under the helmet. The three modern combat helmets: Enhanced Combat Helmet (ECH), Ops-Core, and Airframe, were tested in frontal orientation to determine the effect of helmet geometry. Using the unhelmeted headform data as a reference, we characterized pressure distribution inside each helmet and identified pressure focal points. The nature of these localized “hot spots” is different than the elevated pressure in the parietal region of the headform under the helmet widely recognized as the under-wash effect also observed in our tests. It is the first experimental study which indicates that the helmet presence increased the pressure experienced by the eyes and the forehead (glabella). Pressure fingerprinting using an array of sensors combined with the application of principle component analysis (PCA) helped elucidate the subtle differences between helmets.

Neurotrauma Biomarker Levels and Adverse Symptoms Among Military and Law Enforcement Personnel Exposed to Occupational Overpressure Without Diagnosed Traumatic Brain Injury

“…5 Heavy-wall breaching uses high explosives, whereas sniper rifle fire uses propellant combustion, such that the time for the air pressure to increase and the total duration of air displacement differ. 6,7 Despite this variance, all of these scenarios generate repeated LLOP exposures, 8 and personnel affected report similar symptoms at a greater frequency than their nonexposed counterparts. 9 Understanding LLOP effects has become a health care priority, 10 yet injury responses or health status changes remain elusive.…”

“…Exposure from 0.50-caliber rifle systems regularly exceeds 4 psi . Heavy-wall breaching uses high explosives, whereas sniper rifle fire uses propellant combustion, such that the time for the air pressure to increase and the total duration of air displacement differ . Despite this variance, all of these scenarios generate repeated LLOP exposures, and personnel affected report similar symptoms at a greater frequency than their nonexposed counterparts …”

Fiber Lateral Pressure Sensor Based on Vernier– Effect Improved Fabry–Perot Interferometer

“…Fiber optic sensors are suitable for composite material structural health monitoring given their advantages of compact size and durability [ 4 , 5 , 6 , 7 , 8 , 9 , 10 ]. While significant research has been devoted the consistency and efficiency of this process [ 11 , 12 , 13 , 14 ], there are still numerous defects that may occur during the manufacturing process, including delamination of the layers. Currently, there is no method to measure the pressure applied during the manufacturing process and the real-time deformation of the composite material.…”