Periodic Reporting for period 3 - AIRPOXY (ThermoformAble, repaIrable and bondable smaRt ePOXY based composites for aero structures)
Periodo di rendicontazione: 2021-03-01 al 2022-08-31
2 3R adhesive films for adhesive bonding and welding were produced. A strength of 20 MPa was achieved with 3R laminates bonded with 3R adhesive film. The simulation of bonded structures was developed, and the cohesive zone modelling was selected to describe the behaviour of the adhesive in the model. Regarding 3R welding process, the SQRTM panels with 3R film on the surface were manufactured and welding parameters studied. The need to add an additional adhesive film to the joint area was observed to improve adherence and to level out the irregularities of the contact surfaces. A lap shear strength of around 15 MPa was achieved.
Regarding repair technologies, the NDE technologies were applied on various specimen geometries to detect the defects induced by mechanical testing, and in some cases, they were applied online at specimen level to simulate the in-service scenario. The knockdown effect assessment between the conventional and the 3R composites was evaluated. S HM and mechanical tests of the 3R production processes were performed and the repair efficiency evaluated. 3R composites exhibited a significant repair efficiency with variations that are dependent on the specimen geometry and production process. It was concluded that the most effective repair method is based on the application of pressure and heat in a localized way on the damaged area. Preliminary technical data sheet of the 3R materials were obtained, as well as preliminary guidelines and processing specifications.
2 demonstrators were designed to validate the technologies: A sub-component of a representative fan-cowl (FC) formed by a skin (S), a transverse stiffener (TS) and a longitudinal stiffener (LS), and a sub-component of a representative leading-edge (LE) formed by a nose (N) and two webs (W).
All demonstrators’ elements were manufactured with success: S and TS by RTM, LS and W by DCM, and N with conventional prepreg and 3R film co-cured by SQRTM. Also, a simplified omega profile was manufactured by CCM. Simulation of the thermoforming was performed to provide guidelines to optimize thermoforming set-up. Demonstrators were assembled (FC with 3R adhesive bonding and LE with 3R conduction welding) and tested to assess bonding/welding quality. Different SHM technics were tested to monitor damages in composite structures both for in-production and in-service damages. The repair capability of the 3R resin was demonstrated with success on the TS, where a large area with a delamination was repaired. The sustainability and economic performance of the solutions developed within the project were modelled and assessed through 5 case-by-case scenarios. Regarding human health risk assessment, risk calculations for the 3R technologies was also developed and compared with the conventional ones.
The results obtained were widely disseminated. Thus, to project completion date, 7 peer-reviewed articles and 2 main media articles were published. The results were disseminated at key research conferences and in the final project workshop. AIRPOXY results are attracting a lot of attention both at European & international level. Several companies approached AIRPOXY partners following the final workshop in June 2022 and information release on the web. Agreements with stakeholders are being drafted.