Hail Impact Characteristics of a Hybrid Material by Advanced Analysis Techniques and Testing

Abstract

The design of an aerospace structure using an off-the-shelf composite would involve increasing the gauge thickness until all the design requirements are met. This can lead to an inefficient design, because excess margins will exist for all properties except the one that determines the gauge. The design of a material can be made practical by creating a hybrid composite consisting of two or more types of fibers or resins, each embellishing a particular trait or function to the material. This paper investigates both high- and low-energy hail impact against a toughened-epoxy, intermediate-modulus, carbon-fiber composite using both experimental and analytical means. The effect of introducing ply-level hybridization by substituting up to 20% of the plies with glass-reinforced plies is considered. It is found that delamination can be reduced by this hybridization, but the benefits are dependent on the impact energy and the test conditions. A computational model based on the peridynamic theory of solid mechanics is used to understand the benefits and trade-offs in hybridization.