Impact Damage in Fiber Metal Laminates, Part 1: Experiment

Abstract

Fiber metal laminates (FMLs), a new type of material for use in airframes, are composed of thin plies of metals and fiber-reinforced polymers (FRP). One drawback of conventional composite materials containing only FRP plies is their susceptibility to suffer internal damage due to low-velocity impact while showing little evidence of damage on the surface. Research reported in Part 1, and its companion Part 2, evaluated the resistance of a specific type of FML, glass-reinforced aluminum (Glare), to low-velocity impact. The experiments, a review of previous impact tests, the test program carried out in this project, and its results are discussed. The work confirmed that some consequences of impact on Glare are similar to the damage modes found in FRP composites such as delaminations, fiber breakage, and, ultimately, penetration of the material. On the other hand, in contrast to FRP composites, impact dents are formed that would reveal the impact during visual component inspections. Additionally, it was determined that Glare-5-2/1 laminates had the highest relative impact resistance of those tested.