Michael Braukus

Headquarters, Washington,

(Phone: 202/358-1979)

Pamelia Caswell

Glenn Research Center, Cleveland, OH

(Phone: 216/433-5795)

RELEASE: 00-34

The last time government cannon boomed across the
shores of Lake Erie was during the War of 1812, but a new
laboratory at NASA’s Glenn Research Center, Cleveland, OH,
is now experimenting with ballistics of a different kind.

Building 49 houses Glenn’s new ballistic impact
facility. Its main features are a 40-foot-long gas gun
that can eject projectiles at speeds up to 1,500 feet per
second, or over 1,000 mph, and a high-speed camera that
can capture 2.5 million images per second.

“The whole idea is to watch the impact and see how the
materials struck by the projectiles behave,” said Dale
Hopkins, a structures engineer and team leader for the
design and buildup of the new facility. “It’s not just
whether they survive, but how they deform and fail.”

One of the facility’s main tasks is testing materials
for aircraft engine housings. During rare in-flight
events, if the engine is hit by hail or birds, the engine
housing must contain any fragments and withstand the
severe loads, or forces, that otherwise could cause the
engine to separate from the wing of the airplane. Current
engine housing materials, usually high-strength metal
alloys and non-metal ballistic fabrics, do this job very
well but are very heavy. The new, lighter structures
being considered for this duty must be evaluated for their
ability to withstand such catastrophic events.

“The new facility allows us to use larger, heavier,
irregularly shaped projectiles that look and behave more
like fragments of an engine’s rotating parts. The testing
is much more realistic than before,” Hopkins said.

The facility is also being used to evaluate flywheel
containment materials. The disk in a flywheel, a new type
of energy storage device being considered for use in
satellites and other advanced applications rotates at over
50,000 revolutions per minute. Should the disk fatigue
and rupture, the high-speed particles released would need
to be contained to avoid damaging other equipment or
injuring people.

The materials to be tested include intermetallic
alloys, fiber-reinforced composites and cloth-like
polymers. New engine concepts require materials that can
withstand higher temperatures and higher-speed projectiles
than current containment materials. Similar work at Glenn
over 20 years ago helped prove the worth of the ballistic
materials used in jet engines today, as well as in bullet-
proof vests.

The data taken during these impact tests will also be
used to verify and improve the accuracy of computer models
that predict material response to impacts. Manufacturers
can use these more accurate models to shorten the time and
reduce the cost of bringing new designs to market.

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