Recent development on bonded structures

Abstract

Adhesive bonding is a technology that offers significant advantages for the construction of Aluminium aircraft structures. It is used industrially on several commercial aircraft. This assembly technique combines the stiffness of junctions allowing higher compression loads with a multiple load path configuration with very efficient load transfer between the elements, leading to high damage tolerance. Used together with new Aluminium Copper Lithium alloys (AIRWARE™ technology), weight savings over 20% on typical wing components are obtained. An overview of tests and modelling activities performed by Alcan internally and in partnership with public laboratories to demonstrate the quantitative impact of bonding on damage tolerance and compression stability is given. These include large stiffened panels tested in compression and fatigue crack growth, tests on laminates, and the support to the development of a debond prediction model at TUDelft. An assessment of the technology is proposed from an industrial point of view. Manufacturing issues, in particular non-destructive quality assurance of adhesive bonds and out of autoclave bonding appear to be the main priorities to address in order to widen the use of this efficient technology that could represent a major advantage for future metallic aircraft to be developed around 2020.