Report

Teaser, summary, work performed and final results

Periodic Reporting for period 1 - DEFLECT (DEvelopment of Functionalizable materiaLs for Electrical CabineTs)

Teaser

As the share of electronically controlled tasks in modern aircraft is increasing steadily, the contribution of racks and enclosures for avionics to the overall weight of an aircraft has also reached a relevant level. A big potential for mass reduction exists in this field.The...

Summary

As the share of electronically controlled tasks in modern aircraft is increasing steadily, the contribution of racks and enclosures for avionics to the overall weight of an aircraft has also reached a relevant level. A big potential for mass reduction exists in this field.
The main objective of the project consists in the development of multifunctional, breakthrough material to build the structure of the electrical cabinets. The proposed approach will be able to integrate mechanical and / or electrical and / or thermal elements into the structure. The integration of functionalities into the material would allow reducing the assembly cost of the unit.
The goal is the demonstration that lightweight composite materials are an affordable alternative for the manufacturing of electrical cabinets. This involves the fulfilment of service conditions (mechanical solicitations, temperature and environment), EMI protection and bonding requirements, and material resistance requirements listed in RTCA-DO-160 standard, “Environmental Conditions and Test Procedures for Airborne Equipment”.
It is estimated that the composite solution adopted will allow a 30 % weight reduction (with respect to its aluminium counterpart) and will prevent the need of hazardous surface treatments as the chromic acid anodising and alodine, which use the harmful Cr6+. Even, with a slightly higher initial cost of the enclosure, the composite solution could bring about significant savings if operation costs are considered through the life cycle of the airplane.
The purpose of the project is to efficiently and economically manufacture the components using the materials developed by the consortium and at a scale suitable for industrial uptake. The challenge of DEFLECT project is to contribute to overcome the barriers that materials are currently facing to be introduced in the market as part of advanced materials and advanced manufacturing processes in sectors such as Aeronautics.
Within the first year of the project, the application has been defined and specifications detailed.

Work performed

Conceptual designs with different configurations have been identified, materials have been selected and procured and manufacturing trials in order to set-up the processes have been carried out. A preliminary characterization (there point bending tests and DSC analysis) of the selected approaches has been performed in order to select the approach to be integrated in the final Electrical Cabinet. Trials to embed different elements in the structure has also been performed.

Final results

Multifunctional materials development is strategic to gain competitiveness for aeronautical industry. Multifunctionality can be attained at material, structure or system level. Amongst them material-system integration seems to be one of the most innovative and promising one.
Composite materials will provide important advantages to the design, mainly in terms of mass savings, fatigue resistance and maintenance costs (with respect to its aluminium counterpart). However, there are some features which are specific to the application which have to be improved. Therefore, the objective of this innovation action is the achievement of a fully functional electrical cabinet, considering not only mechanical aspects, but also, electrical, thermal and durability considerations.
To reach this aim, a multidisciplinary knowledge and experience have to be combined in a single structure; the main breakthrough resides in the use of advance composite materials and in the combination of different technologies to give answer to the full set of specifications:
• Lightweight solution based on functionalized composite materials instead of traditionally employed aluminium enclosure
• Taking advantage of the flexibility provided by composite manufacturing processes, the material will be specifically tailored against each of the requirements in order to ensure that the optimum design in terms of performance manufacturing cost and weight will be attained. Different ways to functionalize the composite material will be considered.
• Reduction/replacement of typical electrical harness in a cabinet by electrified structural panels where electrical paths have been embedded inside the structural material, saving space and reducing the assembly times.
• Integration of pluggable connectors in the surface of the structural panels in order to further reduce the assembly time.
• Durability requirements will be met by selecting a resin system able to cope with the harsh environment found in the area where electrical cabinet is to be located.
The fulfilment of all the requirements by a composite material is not trivial. Nevertheless, the risk is minimized thanks to the experience gained by the Consortium who has already worked in the development of composite housings and in the functionalization of composite materials with promising results.
The advances beyond the state of the art of the project lies on considering all the requirements to be fulfilled by the application selected and to take advantage of commercially available materials and technologies developed (at an affordable cost) to combine them within composite processing techniques in order to yield a multifunctional design with same or improved functionality (mechanical, thermal and electrical), lighter weight, reasonable initial manufacturing cost, longer durability and lower maintenance and operational costs.
Nowadays, none of the electrical cabinets of the aircrafts are designed with embedded electrical conductors inside the core of the materials. The majority of the electrical cabinets are made out of aluminium alloys and some of them are made with honeycomb sandwich structures with phenolic matrix based skins. The project proposes two major breakthroughs with respect to current state of the art :
• introduction of new FAR/JAR 25 compatible materials compliant with REACH regulations (doped epoxies, cyanate ester, benzoxazine, …)
• embedding of electrical conductors in the core of the material and related low cost manufacturing processes.
Success of this material-system integration strategy would open a new design route for the future electrical cabinets.
The composite approach can offer significant weight savings (around 30 % with respect to its aluminium counterpart) and improved mechanical performance for equivalent electrical, thermal and shielding performance compared to aluminium enclosures when applied to specified performance requirements. In order to reach this aim, several