Ballistic Impact Response of Kevlar 49 and Zylon Under Conditions Representing Jet Engine Fan Containment

A ballistic impact test program was conducted to provide validation data for the development of numerical models of blade out events in fabric containment systems. The impact response of two different fiber materials Kevlar 49 (E.I. DuPont Nemours and Company) and Zylon AS (Toyobo Co., Ltd.) was studied by firing metal projectiles into dry woven fabric specimens using a gas gun. The shape, mass, orientation and velocity of the projectile were varied and recorded. In most cases the tests were designed such that the projectile would perforate the specimen, allowing measurement of the energy absorbed by the fabric. The results for both Zylon and Kevlar presented here represent a useful set of data for the purposes of establishing and validating numerical models for predicting the response of fabrics under conditions simulating those of a jet engine blade release situation. In addition some useful empirical observations were made regarding the effects of projectile orientation and the relative performance of the different materials. Introduction In the last thirty years the use of aramid fabrics in jet engine blade containment systems has become common. It is recognized that high strength and high elongation fabrics, combined with innovative structural concepts can provide a light weight, effective fan case system that provides the strength required to safely handle impact loads, blade rub loads and the large dynamic loads caused by rotor imbalance. Aramid and other high strength fibers and fabrics have been studied extensively due to their application in a wide range of products such as bullet-proof vests, cut-resistant gloves, tires and sports equipment. However, relatively small amounts of data exist in the public domain for the impact response of fabrics in configurations that are similar to those used in jet engine applications. Containment design is currently largely based on empirical methods but there is strong motivation on the part of jet engine manufacturers to develop numerical models that can be used to help in the design process of fan containment systems, thereby reducing the cost of testing and increasing confidence and reliability in the design. A number of https://ntrs.nasa.gov/search.jsp?R=2008001315