Impact damage evaluation of high performance polymeric composite material systems

The thesis is presented in two parts. In Part I a nitrogen gas gun impact system developed at Virginia Polytechnic Institute and State University is described. Evaluation methods for impact damage resistance and impact damage tolerance as developed by K. T. Teh are presented as a basis for comparative analysis of new materials. Experimental results are presented for six different laminated fiber reinforced composite material systems under investigation at Virginia Tech.

A drop weight tower was used to perform impact tests with testing conditions equivalent to those of the tests with the gas gun. Experimental results from the drop weight test procedure are presented and compared to those of the gas gun. The applicability of the parameters developed by K.T. Teh using the gas gun to other types of impact methods is discussed.

In Part II Kevlar® aramid fiber composites, which are used as high velocity impact protection, are described. Motivation for the study of their mechanical behavior is presented, as well as the approach taken. Results showing the inverse proportionality of mechanical performance to ballistic performance are discussed.