In the Clean Sky JTI new technologies for green manufacturing have been studied in the frame of both GRA (Green Regional Aircraft) and ED (Eco-Design) ITD’s with the objective to realize low weight/eco-friendly aircraft components by competitive manufacturing costs.
To achieve this purpose Alenia Aermacchi, Leader of the GRA ITD and Member of the ED ITD, has conducted several studies and launched various initiatives aimed at the development, optimization and industrialization of Liquid Resin Infusion (LRI) process.
Specifically, Alenia Aermacchi steered the Liquid Resin Infusion (LRI) process executed Out of Autoclave (without pressure) for the one shot manufacturing of wing box stiffened panels in composite material, with the aims to reduce the impact on the weight, on the environment and on the life cycle costs, by using synergies between GRA and ED ITDs, through the support of Clean Sky Members and Partners, selected by the Call for Proposals.
The PLIT project, Topic Manager SICAMB, launched by in the GRA “Low Weight Configuration” domain, arises under this initiatives contributing to provide a scientific approach to the physics of the LRI process by a “numerical process simulation model”, to study the resin flow during the impregnation. This model shall be used to identify possible causes of non uniform distribution of resin flow that may cause dry spots, poor saturation of the pre-form, partially filled composite parts, defects etc.
Innovative tools have been designed, starting from Clean Sky Members indications, and realized for the wing box stiffened panels manufacturing to verify the simulation results.
General stringer-stiffened panels are, from a weight perspective, the optimal configuration for wing covers. While for large CFRP prepreg Automated Tape Laying (ATL) is the current preferred manufacturing technology in the aeronautic industry due to the high level of automation and reliability, for small and medium size parts closed-processing Liquid Composites Moulding (LCM) technologies are currently being used such as the Resin Transfer Moulding (RTM) and Vacuum Assisted Resin Transfer Moulding (VARTM) or Liquid Resin Infusion (LRI).
All these technologies rely on the basic concept of injecting or infusing the resin into the fibrous reinforcement assembly, either in a closed mould in the case of an RTM process, or in a vacuum bag moulding in the case of a VARTM process.
These processes carry numerous advantages:
- improved hygiene and safety and cleaner processing without volatiles,
- lower storage costs,
- indefinite shelf life (for the textiles),
- lower energy costs (out-of-autoclave), and
- ability to manufacture integrated structures having complex geometries.