Effects of Variable Helmet Weight on Human Response to -Gx Impact.

摘要

Helmet-mounted systems (HMS) may increase the potential for aircrew neck injury during aircraft ejection due to the increase in dynamic loads generated in the cervical spine as a result of the change in helmet inertial properties. A series of tests were conducted on a horizontal impulse accelerator with human subjects wearing forward-weighted helmets to investigate the effects of helmet inertial properties and bracing on human response to short-duration frontal (-Gx) impacts, as might be experienced during the seat deceleration and parachute opening shock phases of ejection. The tests demonstrated that some subjects began experiencing discomfort and pain when wearing 3.5 lb helmets at 10 G seat accelerations. While overall neck loads demonstrated little or no gender difference, the female subjects were on average unable to sustain as forceful a brace during pre-impact as the males, which may account for their higher head accelerations and higher percentage of reported adverse effects. Pilot bracing techniques may therefore have a beneficial effect on injury risk by off-loading some of the neck loads experienced during ejection.