Class: BE210
Group: T8
Members:
Chou
Lukasik
McGrath
Torga
Date: April 2004
Abstract:
Energy absorption and rebound minimization are desirable
characteristics in safety devices such as protective helmets. In
bicycle helmets, the helmet must manage all the severity of the impact
and limit the shock transmitted through the helmet to the cyclist. It
is the purpose of the helmet to attenuate rather than eliminate shock,
and to manage the impact by deformation. The helmet is deformed until
the cyclist’s head is slowed to a complete stop or the helmet is
crushed to its minimum thickness . In a study by McIntosh, et al ,
different designs of rugby helmets were tested and head acceleration
and energy absorption were measured. Impact energy attenuation of
different configurations of polyethylene foam was determined by
testing. It was discovered that small design changes could
significantly change the impact energy attenuation. A correlation was
found between thickness of foam used and impact energy attenuation. It
was also noted that when designing a helmet, it is difficult to
construct a design that will perform well in both repeated, low energy
impacts that would only result in cosmetic damage and high energy
impacts that would cause concussions.