Helmet-Mounted Displays: - USAARL - The - U.S. Army

Biodynamics 7
B. Joseph McEntire
Helmet Performance
The role of the basic helmet historically has been to provide protection.
This role has not changed but has been expanded. While initially providing
impact protection, the helmet’s protective role has grown to include hearing
and eye protection. Now, the helmet is expected to serve additionally as a
platform for mounting a display. However, this new function must not
compromise the helmet’s primary requirement to provide protection.
To design an integrated HMD which can meet both the old and new
requirements, several helmet parameters and associated factors must be
considered. These include the biodynamic characteristics of mass and
center of mass (CM), impact attenuation, the design issue of HMD
frangibility (breakaway capability), the fitting system; acoustical protection
and communication issues; and eye protection from particulate matter as
well as sun glare and directed energy (e.g., lasers).
Biodynamics
Helicopter aircrew helmets are becoming more sophisticated with
increased mission requirements and their use as platforms for HMDs. This
increase results in additional mass being supported on the aircrew’s head,
often with an asymmetrical CM. The functional requirements of the
helicopter pilot helmet have grown considerably. Traditional helmet
functions include head impact protection and service as a mounting
platform for communication systems, hearing protection, eye protective
visors, and on occasion, oxygen systems. Increases in threats and
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