Comparison of the Low and High Velocity Impact Response of Kevlar Fiber-Reinforced Epoxy Composites

Failure mechanisms of basket weave and 3-D braided Kevlar-fabric reinforced epoxy composites under low and high velocity impacts have been studied. The purpose of this study is to examine the initiation and development of damage under these two widely differing loading conditions on 2-D and 3-D structure fabric composites. The critical evaluation of post-damage composite panels was conducted using a combination of high magnification photography, optical microscopy, and scanning electron microscopy (SEM). The first objective, quantification, has been realized in principle with regards to laminated composites, and it has been demonstrated that dispersive failure occurs in these composites. The second objective in this work established the relationship between kinetic energy absorbed and the damage tolerance of inter-leaved composites as assessed by the impact tests. High velocity impact loading by a small projectile is generally more detrimental to the integrity of a composite structure than low velocity dropweight impact loading.