Thesis Details


Thesis Title: Optimization of ballistic resistant soft armor properties using a needlepunched nonwoven structure
Thesis Author: Gregory Thompson
Abstract: 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.