HUMAN VERTICAL IMPACT TESTING OF AUTO-SEPARATION NIGHT VISION GOGGLE HELMET SYSTEMS

摘要

A new generation of night vision goggle (NVG) systems allows pilots to greatly improve situational awareness and targeting capabilities during nighttime combat missions. However, the integration of such systems results in an increase in head supported weight and a change in inertial properties, which may necessitate the need for an auto-separate mechanism to lower cervical loads and decrease susceptibility to neck injury upon ejection. NVG systems were previously tested on a Vertical Deceleration Tower (VDT) using the Hybrid III manikin with successful separation during 11 G impacts. However, as the Hybrid III neck poorly reflects human neck flexion, a validation study using human subjects was conducted for two types of NVG systems, the Panoramic NVG (PNVG) Block 1A and NVCD (Night Vision Cueing Display). Additionally, manikins with their heads tethered to the headrest to simulate human bracing were tested under identical conditions. In contrast to the original manikin test results, zero separations occurred for the human subject pool or modified manikin tests for either NVG. Although the maximum seat acceleration for the human subjects was only 10 G, some separation would have been expected since the resultant head accelerations of some of the humans were similar to those experienced by the original manikins. Both male and female subjects tolerated the neck loads well with no medical incidents being reported during any of the tests, leading to the conclusion that these systems are likely safe to wear during the ejection catapult phase. However, modifications to the stiffness of the separation mechanism are recommended in order to ensure full separation prior to the less controllable parachute opening shock phase.