The substitution of metal parts by composite materials in aircrafts is a key approach within the general trend of improving the fuel efficiency and meeting environmentally friendly designs. Metals are heavier than composites and very usually require hazardous treatments to maintain their properties in acceptable levels that should be removed from the production line. Also, carbon fiber based materials present extremely high specific mechanical properties allowing for a significant weight optimization.
Actually, the application of composite materials is not only restricted to primary structure elements, but more and more metal components of the systems of the aircraft are being manufactured now in composites. However, the intrinsic properties of metals such as electrical conductivity are challenging the progress in the “carbonization” of some elements. Thus, the manufacturing of these parts in composites needs of novel material developments and strategies to meet all the requirements.
The environmental control systems (ECS) are essential systems of the aircraft that require of high electrical conductivity to discharge the static electrical charges produced during operation. Currently, some of the ducts of the ECS were successfully manufactured in polymer compounds. Nevertheless, the limited electrical conductivity of the composites that can be employed implies the use of metal braids to assure electrical continuity of the device, which add weight to the system. In this scenario, the ECOFUNEL project aimed to create new enhanced compounds with the objective of suppressing the extra weight of the braids. The technical approach for accomplishing the objectives included the use of specific fillers for the compounds in combination with reinforcements that enabled the enhanced electrical feature while keeping appropriate levels of mechanical properties.
