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Hybrid laminates. Industrialization for aircraft nose fuselage

Final Report Summary - HYBRIA (Hybrid laminates. Industrialization for aircraft nose fuselage.)

Executive Summary:
HYBRIA Project entitled “Hybrid laminates. Industrialization for aircraft nose fuselage.” is a FP7 project of 24 months, which has begun on March 2012, the 15th and has ended on March 2014, the 14th. The project is related to the CfP of Clean Sky: SP1- JTI-CS-2011-03 and it is being developed in the frame of the Green Regional Aircraft programme with activity code: JTI-CS-2011-03-GRA-01-039. HYBRIA consortium is composed of only one single partner; FIDAMC, whose facilities are located in Getafe (Spain).

The use of layered composites in aircraft fuselage structural components offers the opportunity to embed interleaved layers of different materials in the skin laminates so that additional performances may be added while maintaining the structural efficiency. The presence of layers of damping materials inside the composite laminate normally results in an important reduction of mechanical properties. The goal is to design composite laminates with integrated acoustic insulation without compromising the mechanical performance of the composite structure.

After the materials screening/selection and architectures/mechanical studies carried out within the former COMPASS project, the aim of HYBRIA project is to develop hybrid structures by means of industrial manufacturing processes. During the project, three curved stiffened panels representative of the GRA cockpit fuselage were produced: hybrid skin fuselage with co-cured stringers of different shape section. Several manufacturing trials were carried out during the production of the demonstrators with the intention to validate innovative manufacturing concepts that will be implemented in the whole GRA cockpit production. NDT as well as dimensional analysis of the demonstrators were performed in order to assess the quality of the specimens produced.

HYBRIA Project supports the development of a strong European expertise in both innovative materials development and composites materials process which propels European citizens at the edge of innovation and expertise in these fields: this will guarantee to maintain high added value parts manufactured in Europe, ensuring an effective competitiveness.


Project Context and Objectives:
Integration of acoustic damping function in a single material system will permit enhancing the structural behavior and diminish overall structural weight by reducing redundancies between subsystems and functions. To meet the objectives of the project, work has been split up into four main work packages which related purposes are described hereafter.

First stage of the project was dedicated to explore potential issues regarding the large scale manufacturing of hybrid panels with acoustic material insertion. Objective of WP1 was to complete the materials and configurations screening previously carried out in COMPASS project which allows selecting the hybrid skin architecture, definition of the manufacturing process and CAD model generation. Additionally, flat panels were produced for being tested subsequently within WP4.

WP2 was devoted to tooling design and manufacturing. The tooling basically consisted of two tools for the hot-forming of the stringers and a male PEAU for both integration and curing phases. Additionally, two types of innovative caul-plates were manufactured by FIDAMC in order to study the effect of different stiffness of the caul-plates on the aerodynamic surface of the specimen among other aspects.

The objective of WP3 was to validate, by means of the manufacturing of three curved stiffened panels representative of the GRA cockpit fuselage, different manufacturing concepts that will be implemented in the whole GRA cockpit production. Several manufacturing trials were carried out during the production of the demonstrators. Within this WP, NDT as well as dimensional analysis of the demonstrators were performed in order to assess the quality of the specimens produced.

Finally, objective of WP4 was to complement the material properties data base from COMPASS project, carrying out vibro-acoustic, erosion, BAI, buckling and low energy impact tests. Acoustic-vibration tests will be carried out in order to produce experimental data against which damping theoretical model will be compared to. Additional mechanical testing, necessary to complement the investigation in those multifunctional configurations explored, was accomplished within this WP as well.

Project Results:
See enclosed file

Potential Impact:
Regarding acoustics, future aircraft generation has highly demanding requirements to produce designs that will be increasingly more attractive for airlines and comfortable for passengers. The fact that next generation fuselages will have an important amount of composite materials offers the opportunity to reduce engine and aerodynamic noise, as well as vibration transmission to the interior of the aircraft using acoustic multifunctional lay up. The most common method to minimize noise and vibration propagation to the interior of the cabin in current aircraft is the use of add-on parts that contribute to partially reduce noise and vibration levels. However, many add-on parts are required and this leads to high material costs, high labour costs and increased weight of the aircraft.

HYBRIA project has demonstrated the feasibility of acoustic material insertion within a CFRP structure by means of industrial manufacturing process without significant decreasing of properties. Therefore, assembly operations are simplified as well as overall structure weight is reduced. Moreover, HYBRIA project has proposed manufacturing processes which allow tooling simplification as well as reduction of ancillary materials consumption for the production of composite structures.

Development of new hybrid fuselage configuration, together with one-shot process which allow co-curing hybrid skin, is a key enabling technology for achieving a reduction in weight and processing time, which will involve a notably reduction of consumption and manufacturing costs respectively.

Spread of use of multifunctional materials in aircraft fuselages will result in:
• Reduction of engine and aerodynamic noise in the aircraft cabin.
• Reduction of vibration transmission to the interior of the aircraft.
• Less assembly steps in the production process.
• Less labour costs related to these assembly steps
• Less use of bolts and rivets: diminution of aircraft parts weight
• Lower fuel consumption due to diminution of aircraft parts weight and reduction of industrial production steps (less energy required as less parts produced separately).
• Energy savings and decrease of material scraps derived from the tooling simplification and the reduction of the ancillary materials consumption during the manufacturing of CFRP structures.

Globally, impacts on society will be:
• Diminution of manufacturing costs and easier and cheaper maintainability: airlines operations savings will benefit all the stakeholders.
• Diminution of time production.
• Lower carbon emission, which is in line with European policy objectives in the frame of Clean Sky programme.

List of Websites:

Bernardo López Romano: Bernardo.lopez@fidamc.es
Pedro Nogueroles Viñes: Pedro.nogueroles@eads.com
Sofía Delgado Labrandero: Sofia.delgado@fidamc.es

www.fidamc.es