Level 1 has been a preliminary phase to confirm the starting TRL and to identify the most critical parameters that affects the process including the way to control them. In the deliverable D1.2 in accordance with the manufacturing trials characterized to assess process parameters for technologies/configuration under trade, the process procedure including the check list have been defined.
The main conclusions of this phase are:
- As agreed with standards defined, the thickness tolerance of the specimens is 2 mm ± 0.08. RTM trials fulfill this requirement.
- Flatness deviation is similar in both processes.
- Seven trials were manufactured by LRI and RTM manufacturing technologies. Low percentage of porosity is present in RTM trial.
With Level 2 and 3, the RTM technology has been promoted to TRL4 – Small Scale of Prototype.
The manufactured specimens (i.e. straight frame and curved frame) prove that the RTM basic technological elements are well known and integrated in a laboratory environment. The level of performance of the frame prototype, (i.e. quality level, structural properties, allowables), is consistent with the requirements of item application.
Within deliverable D6.1 the affordability of the manufacturing process and relative methods to design the aerospace parts, the frame, including a real test case have been validated. Compression, tension and 3 point bending tests have showed key ratio of correlation, close to 100%, and a behavior of the physical test in accordance with the simulation made using material properties selected from phase 1.
By this effort standalone prototype have been implemented and tested at full-scale level using a data sets of realistic cases.
For these reasons it can be concluded that with the TRL4 is validated.
The Full Scale level of the pyramid approach represents the evolution of TRL from 4 to 5, large scale prototype.
At this stage, the fidelity of the process has significantly increasing. The advanced technological elements have been developed to support a full possible application, (i.e. full scale frame, integrated in a fuselage barrel with sub-assy components). TRL5 means that the full scale prototype can be tested in a ‘simulated’ or realistic environment and that the prototyping implementations conform to target environment and interfaces.
For these reasons, full scale demonstrators have been made and cutted and inspected for Preliminary Production Validation (PPV) to demonstrate the compliance with manufacturing expecation.
The technology can be named as Short-term Ready and it is possible within 2-3 years to be close to the aerospace qualification considering moderate investment in R&D. In fact, the analysis made during Cofrare 2.0 project showed that labor cost still impact the convenience of RTM technology for massive production such as frames for aerospace fuselage. From technical point of view, at the same time, the approach carried out in this project for the lamination of the dry NCF fiber is not affordable in an industrial environment because it is time consuming.
