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Abstract:
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Needlepunching is a rather simple operation, yet a
variety of properties can be realized in a needled web
structure through varying different aspects of the process.
By understanding the variety of properties a single
operation can produce, the product can have properties
specifically suited to end uses.
In 1966 this approach was used by Natick Laboratories
in the development of a needlepunched ballistic resistant
felt. The study found that a needlepunched structure could
be produced at one-third of the weight of a woven duck
fabric while keeping 80% of its ballistic resistance.
Although work done in this area proved significant, little
work has been published since then.
with improvements in manufacturing techniques, and the
new high performance fibers such as Kevlar and Spectra that
have been developed, a needlepunched structure was modified
to create a structure more capable of performing up to
ballistic standards, as well as giving a much lighter weight
structure as compared to conventional soft body armor.
The variables contributing to ballistic resistance in
this study were evaluated through both subjective, and
objective means. The information showed that a
Spectra/Kevlar blend, with punch densities in the range of 700 punches per square inch, gave the highest V50 values.
Also as web layers increased, V50 increased.
Based on the information gathered from this thesis,
needlepunching a blend of Spectra and Kevlar is a viable way
io produce a light weight flexible structure that is
competitive in ballistic resistance, yet one-third the
weight of, soft body armor structures in use currently. The
properties of this structure may improve the comfort of a
bullet proof vest, and therefore increase the percentage of
law enforcement officers that use them. Various properties
of the structure would have to be optimized before it could
pass standards put forth by the Department of Justice for
soft body armor use. If these standards could be passed, the
needlepunched structure created by this thesis may be able
to compete against structures in use currently.
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