Disruptive fuselage study by Topological Optimization & Additive Manufacturing

STELIA is French aerostructures leader and major worldwide player for design and production of primary structure of aircrafts. STELIA produces every year more than 650 noses and fuselage sections and 6 million elementary parts and panels. For 5 years, STELIA leads research programs dedicated to additive manufacturing technologies.

Stelia Aerospace has produced, through additive manufacturing, a metallic fuselage panel complete with integrated stiffeners. This one-meter-square “self-reinforced” demonstrator panel was robotically produced through an aluminum wire arc additive manufacturing process, and that it represents a “disruptive design”.

Stiffeners are typically attached to panels with fasteners or through welding. Alternatively, panels with integrated stiffeners can be milled from solid metal, but that process leads to substantial material waste.

The parent of the fuselage breakthrough is topology optimization research and technology project DEFACTO (DEveloppement de la Fabrication Additive pour Composant TOpologique). Through topology optimization, STELIA designers and engineers have created a fuselage skeleton with strategically placed stiffeners directly 3D printed onto the panel surfaces. Typically, these stiffeners would be affixed to fuselage panels using bolts and screws. By avoiding the need for further components, 3D printed panel stiffeners are less susceptible to weakness, creating a much more stable airplane body.

The aim is to take benefits of additive manufacturing: freedom of conception (no assembly constraint), reduction of production waste (buy-to-fly reduction), and simplification of production process (reduction of assembly). For manufacturing this demonstrator, Stelia takes into account all operations, from material deposition to part finishing (machining) into design-to-print philosophy.

The main challenge is to prove the viability of additive manufacturing to develop an industrial process which takes account of certification and cost aspects. This one includes no defect in produced part, capability of maintenance and no destructive testing to detect possible crack.

Keywords: Fuselage, Primary structure, Topological Optimization, Additive Manufacturing, 3D printing, Wire Arc Additive Manufacturing, Direct Energy Deposition