Fatigue Behavior of Fiber/Metal Laminate Panels Containing Internal Carbon Tear Straps

Abstract

This paper presents a novel hybrid structural concept for improving the damage tolerance of a thin panels subjected to fatigue, such as the skin of an aircraft fuselage. The concept is based on the hybrid fiber/metal laminate technology used as a fuselage skin material in the Airbus A380. By tailoring the stiffness of an fiber/metal laminate locally by variation of the reinforcing fiber, a damage-tolerant feature analogous to the bonded titanium tear strap in monolithic metallic fuselage skins can be introduced internally within the laminate, without variations in laminate thickness. The overallmerits of this concept are discussed, including a preliminary experimental investigation into its improvements to damage tolerance of standard fiber/metal laminates. Overall, the concept was shown to result in nearly a twofold reduction in crack growth and up to a 25% increase in residual strength for fatigue cracks located near the damage-tolerant feature.