Cost Effective Reinforcement of Fastener Areas in Composites (CERFAC)

A B-stage curing method had been developed to reinforce fasterner areas in an aircraft floor beam. The developed cure kinetic models, and effect of co curing on the bearing strength is investigated.

Floor beam to omega frame connection in a fuselage, including reinforcement patches.

Topics related: B-Stage Co-curing, Vario-therm Compression Resin Transfer Moulding, genetic optimisation algorithms, cure kinetics modelling, rheological modelling

Website of the project

Thin Ply Technology offers unit plies four to six times thinner than conventional composites; by reducing ply thickness, one can gain improvements in the mechanical properties by reducing ply coupling, and having greater flexibility in ply angle and lay up. This opens a new range of high-end applications in aviation, space and sport.

Optical cross sections of two carbon fibre epoxy thin ply laminate with aerial weight of 150 gsm (left) and 29 gsm (right), which is the minimum fibre areal weight of the tapes produced by Createx AG

It is essential to scientifically characterise the benefits of the TPT to enable their application in high performance composite applications.

Our research is

• Developing of experimental validation of cure kinetics models and rheological models for the resins used in the material.
• Optimising the out-of-autoclave production process ; determining the appropriate resin fraction in the pre-preg, optimised consumables and de-bulk pressure, time and temperature in order to achieve a excellent consolidation  in industrial production conditions.

Topics related: Thin Ply Technology, prepreg development, vacuum processing of high performance materials, cure kinetics modelling, rheological modelling

The mission of this European project is to develop breakthrough technologies to significantly increase the environmental performances of airplanes and air transport, resulting in less noisy and more fuel efficient aircraft, hence bringing a key contribution in achieving the Single European Sky environmental objectives.

Our institute is part of the Eco-Design cluster.
Eco-Design will focus on green design and production, withdrawal, and recycling of aircraft, by optimal use of raw materials and energies thus improving the environmental impact of the whole products life cycle and accelerating compliance with the REACH directive.

1. Composite plate 2. High-voltage fragmented plate 3. SEM image of a fragment (133x)

Topics related: Thermoset and Thermoplastic CFRP Recycling

Website of the project

The failure of a state of the art CFRP laminate is almost always governed by compressive failure in fibre direction (driven by the comparatively low matrix stiffness, resulting in buckling of single fibres at the microscopic level) or transverse strength (driven by the matrix strength at the fibre to matrix interface). Therefore, there has always been a high interest to enhance the properties of the fibre to matrix interface. One novel approach addressing those issues, referred to as multi scale composites (MSC), is to attach carbon nanotubes perpendicular to the surface of the carbon fibres and thereby reinforce the composite material both on the nano- and micro scale.

The aim of this project is to understand the structure property relationship of these materials and to maximize the mechanical performance when used in CFRPs. This will be addressed in a first stage by improving the interfacial strength at a single fibre level. By upscaling to the lamina level, the CNTs from neighbouring fibres will interfere, leading to additional synergistic effects in increasing the mechanical properties of the MSC. However, additional challenges in impregnation have to be addressed within this second stage. The outcome of this project will help to substantiate the benefits of these materials for lightweight structures. Further it contributes to the understanding of the associated processing and impregnation issues for composite materials.

Topics related: Multi Scale Composites, Carbon nanotubes