Damage Tolerant Repair Techniques for Pressurized Aircraft Fuselages

Abstract

Concerns over the safety of the continued use of aging transport aircraft have been voiced in the industry. A key component in the structural integrity of aging aircraft is the damage tolerance of fuselage structural repairs. The investigation focuses on the analysis and testing of contemporary repair methods and develops two improvements. The first technique, known as soft patching is appropriate for damage tolerant riveted repairs to incidental fuselage damage. Soft patching involves the use of high strength, moderate elastic modulus GLARE 3 fiber metal laminate patches. They extend the fatigue life of riveted repairs to monolithic aluminum fuselages while reducing life cycle costs. The second technique involves bonded crack patching of intact fatigue cracks in fuselage skins. An easy to use analysis program is presented along with analytical and test results of a low cost, high performance patch material known as GLARE 2. The findings demonstrate that GLARE 2 can replace the expensive boron/epoxy composites used in fuselage crack patching applications. Repair, Fatigue, Damage tolerance, Fuselage, Structures, Crack patching, Adhesive bonding, Surface pretreatment, Riveting, Advanced composite materials, Fiber metal laminates, GLARE, coefficient of thermal expansion.