Abstract

The present document describes a new concept of composite fuselages manufacture, oriented towards the minimization of manufacturing costs through the generation of a monocoque fuselage structure, that allows to reduce the number of rivets and also the components joining operations, by means in addition of a process that avoids the use of molds, finally producing a lightweight and adaptable structure. The process in turn facilitates a high level of automation in the manufacture of composite fuselages and opens the door to a greater acceptance of this application in the aeronautical sector. The document outlines the design of the manufacturing process and the implementation of that particular production process for the manufacture of a real-scale concept demonstrator within the MTorres facilities, showing the reduction of the production cycle and the general manufacturing costs based on the simplification of the structural design and the integration of components into just one piece. Other additional variables that can benefit the reduction of costs and cycle times of the production process are also evaluated.

Abstract

The aim of this project had been the infusion specimens manufacturing to support design, analysis and qualification for the “Outcome Lower Skin” pyramid structural tests inside the Clean Sky 2 programm. It is the reinforcement lower skin structural tests pyramid for the C295 military aircraft from Airbus Defence & Space.

Along the project UD dry fiber manufacturing process had been developed until to obtain an automatic, robust and efficiency process in order to be able to manufacture a lower skin with stringers and spars integrated and that will be able to compete with the typical prepreg process with regard to fabricability, ratio, performance and cost.

The manufacturing process includes the dry fiber pre-forms automatic lay-up by AFP (Automated Fiber Placement), a hot-forming process for the stringers and finally a process infusion by VAP (Vacuum Assisted Process). To achive this goal, the AFP has been set up to optimize the laying parameters for the processing of the material to be used (½” Hexcel Hi-Tape fiber) and RTM6 resin. On the other hand, several tests of hot forming had been carried out modifying process variables, and several infusion bags configurations had been used to stringers and skin integration by infusion (VAP) until to find the key process parameters to obtain valid parts for the structural test pyramid.

Abstract

FIDAMC(Fundación para la Investigación, Desarrollo y Aplicación de Materiales Compuestos) ,  has been investigating different technologies, under the frame of several research projects funded by Clean Sky initiatives and Spanish governmental entities, in order to demonstrate that  thermoplastic can be directly manufactured via automation without autoclave consolidation and the full integration of the structure by co-consolidation method fusing together the skin and stringers in only one melting step. Our Center is currently involved in an interesting project with a complete manufacturing solution of a thermoplastic wing skin using Automatic Fiber Placement (AFP) with assisted laser system as heating source techniques. This new Out-of-Autoclave procedure will be validated with ground/flying tests in 2020. This paper provides an overview of several research projects aimed to develop the automated lamination and in-situ co-consolidation technology and includes a review of automated methods to lay up PEEK prepreg from the first AFP head, in cooperation  with the Spanish supplier MTORRES and installed six years ago in FIDAMC, the evolution of this machine and the up-to-the minute configuration of new Multi-tows head to produce the feasibility demonstrator panel with co-consolidated "T" shaped stringers and scale up the methods to the final stiffened wing panel to incorporate in Clean Sky 2 as Flight test Bed developed by Airbus.

Abstract

The current work has been performed in the context of FUSINBUL, an European project framed within CleanSky2 research programme funded by the EU’s Horizon 2020 (Grant Agreement nº 831946). The scope of this project is to accomplish the full barrel demonstrator tests, needed to certify the new conception of fuselage created and manufactured in the Green Regional Aircraft context. Two advanced manufacturing processes for composites materials (prepreg cobonding process in autoclave and LRI infusion process out of autoclave) are developed and validated to achieve full scale innovative pressure bulkheads for Regional Aircraft Fuselage barrel on-ground demonstrators. The design of the tooling has taken into account the main needs of both manufacturing processes to carry out the bulkheads and the industrial requests. In addition to this, innovative tool technologies have been developed and applied, such as cast aluminium by lost foam casting, precise but robust indexing system split and seal system of tool too large to be fabricated one shot, then precisely assembled with no gap or step. For both manufacturing processes, the most advanced techniques of lay-up are used to reduce labor costs and increase the level of industrialization in serial production to achieve bulkheads with a diameter of 3.5m and the required standards in aeronautical industry.