Diffuse brain injuries are very common in side impacts,
accounting for more than half of the injuries to the head. These
injuries are often sustained in less severe side impacts. An
English investigation has shown that diffuse brain injuries often
originate from interior contacts, most frequently with the side
window. They are believed to be mainly caused by quick head
rotational motions.
This paper describes a test method using a Hybrid III dummy head
in a wire pendulum. The head impacts a simulated side window or an
inflatable device, called the Inflatable Curtain (IC), in front of
the window, at different speeds, and at different impact angles.
The inflated IC has a thickness of around 70 mm and an internal
(over) pressure of 1.5 bar. The head was instrumented with a three
axis accelerometer as well as an angular velocity sensor measuring
about the vertical (z) axis. The angular acceleration was
calculated. The head impact speeds ranged up to 7 m/s, a speed at
which the Inflatable Curtain barely bottoms out. The recorded data
for linear acceleration, angular acceleration and angular velocity
were compared with corresponding threshold values found in the
literature.
It was concluded that the Inflatable Curtain has the potential
to substantially decrease the risk of sustaining diffuse brain
injuries. The IC reduced the maximum linear acceleration and HIC up
to 70% and the peak angular acceleration up to 70%, depending on
the contact angle between the head and the IC. The peak angular
velocity was reduced up to 30%.