Out-of-autoclave manufacturing of large integrated structures using thermoplastic composite materials

This paper describes the design and manufacture of an integrally-stiffened curved panel for space launcher applications, using advanced thermoplastic composite materials. This stiffened panel is based on the design of the 2/3 interstage of the Ariane 4 space launcher. The panel is a 1/8th section of the original structure with approximate dimensions of 2m x 1m, consisting of a curved base panel and T-section stiffeners. The base and the stiffeners are manufactured using novel out-of-autoclave processing and assembly techniques. Electrically-heated tooling technology enables the consolidation of the base skin and the thermoforming of the stiffeners using vacuum pressure alone. To provide the necessary heating, the proprietary mould tooling employs a metal tool with ceramic/glass-fibre panels with embedded electrical heating elements. The parts are assembled using an amorphous interlayer bonding process which takes advantage of the ability to fusion-bond thermoplastics quickly and without the use of adhesive or fasteners. Test panels verified the design and demonstrated the buckling capability of the structure. A full-sized manufacturing demonstrator was assembled.