“Test Methods for analySis OF Infusion pAnels” (SOFIA)

Project Information

SOFIA

Grant agreement ID: 101007984

DOI

10.3030/101007984

Project closed

EC signature date 11 December 2020

Start date 1 March 2021

End date 31 July 2023

Funded under

• SOCIETAL CHALLENGES - Smart, Green And Integrated Transport

Total cost

€ 639 496,25

EU contribution

€ 498 339,50

Coordinated by

ALESTIS AEROSPACE SL
Spain

Periodic Reporting for period 2 - SOFIA (“Test Methods for analySis OF Infusion pAnels” (SOFIA))

Reporting period: 2022-05-01 to 2023-07-31

Summary of the context and overall objectives of the project

The aim of the project is to validate new proposals for thermoset composite manufacturing via tests based on coupons (Level 2 Tests) and a test based on component (Level 3 Test).
Today most structural composite components are manufactured by means of classical methods like the use of pre-impregnated fabrics or tapes which are laid-up on tools, vacuum bagged and cured in an autoclave under elevated pressure and temperature. These classical methods are energy intensive, expensive and have a higher environmental footprint.
The use of infusion as the process to add resin to the dry fiber together with the automatization of tape layer process will allow to reduce energy consumption and time and, in consequence, costs and the environmental footprint of manufacturing processes will also be reduced.
The project addresses the validation of the structural behavior of a defined thermoset panel consisting of stiffeners and skin manufactured using novel techniques indicated in previous paragraph.
Test results shall demonstrate the competitiveness of the newly developed manufacturing process and the potential of this technology. The response of the structure to defined static loads will also improve the understanding of the chosen manufacturing concept and design. The performance capability of the automated tape layer process with dry UD tape and its subsequent infusion shall be validated by a specified testing program.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

Work to be done in SOFIA project has been structured in 5 Work packages (WP in the following) whose content is briefly summarized hereafter.
Work Package 1
Finished in previous Report.

Work Package 2
One of the activities included in WP2 has been the elaboration of Level 2Test Plan proposal (D2.1) describing tests to be carried out in Level 2 where finally 4 tests were selected: Unfolding, Compression After Impact (CAI), Interlaminar Fracture Toughness (GIC) and Seven Point Bending (SPB).
Panels requested in D1.1 Level 2 test specimens sizing for the extraction of L2T specimens were provided in 2 shipments dated in January and March, 2022.
Design and manufacturing of tooling necessary for the performance of L2T (only identified the need for SPB test) has also been performed during this reported period as part of WP2 tasks.
Workshop of Level 2 Tests was celebrated by teleconference in March 2022 as a prelude to some Preliminary tests of each type (Unfolding, CAI, GIC and SPB) performed in April 2022
Level 2 experimiental Tests performed by US with ALS supervision obtaining the following objectives:
1) CAI tests results provided a better estimation of DTA for the different laminates tested
2) Unfolding tests results provided info to calculate an allowable value of Interlaminar Normal Stress from ASTM D 6415/D 6415M – 06ae1
3) GIC test were correlated by means of a FEM, obtaining promising results about specimen initial stiffness, deformation and behaviour during crack tip progression.
4) SPB in symmetric and anti-symmetric configurations were also correlated with FEM. Numerical correlation provided important info as the location of the crack initiation and evolution of the damage.

Tests results and numerical correlations are included in Delivery D2.2 Level 2 Test Report & LCA Data delivered in Sepbember2023. Delivery of D2.3. has been performed in October 2023.

Work Package 3
Delivery of D3.1 including the test plan for L3T in December 2022
Design and manufacturing of tooling for L3 Test were also accomplished, so L3T could be performed in July 2023.
Delvery of D3.2 has been postponed due to problems of convergence and it is expected do be delivered in November 2023.

Work Package 4
Dissemination and Communication activities performed as part of WP4 tasks are provided in next paragraphs.
Creation of a logo and brand for the project, present in templates for reports and presentations.
Creation of a specific web sites for project SOFIA within ALESTIS AEROSPACE website (https://www.alestis.aero/) and APPLUS website (https://www.appluslaboratories.com/global/en/about-us/innovation/sofia-project)
Presence of ALS and APPLUS in JEC world (celebrated in Paris from 03 to 05 May 2022) and USE in MATCOMP 2021 (to be celebrated in June 2022)
Presence of ALS and US in MATCOMP21 (celebrate in June 2022 due to COVID reasons) where SOFIA project was explained in an oral presentation.
Presence of ALS and US in COMPTEST23 with a poster and a short video where SOFIA project was described.
Presence of APPLUS in different expos such as:
-AEROSPACE & DEFENSE MEETINGS SEVILLA
-Farnborough Airshow
- European Rotors
-Aeromart
- FEINDEF
-PARIS AIR SHOW LE BOURGET

Work Package 5
Activities of Project Management and Coordination performed. All deliveries in WP5 haven been delivered.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

Results from Level 2 and Level 3 Tests are promising and infusion is called to stand in a remarkable position to be taken into account in the near future as a leading manufacturing procedure.
Mechanical properties of material are promising and component behaviour in numerical simulations performed seems appropriate. However, as the object of the project is the validation of a new manufacturing process, it is key to study the real behaviour of the material as part of an aeronautical structure widely used (as omega stiffened panel) manufactured using a combination of automatized lay up tape process and infusion in order to identify defects derived from the novel manufacturing process.

Level 2 and Level 3 test are finished and results processed, so a preliminary evaluation of how competitive novel manufacturing process is compared with classical manufacturing process can be performed.

For this new process to be considered as possible substitute of current one, it is expected similar (or better) level of quality and mechanical behaviour with the reduction of energy and time (reducing cost and environmental footprint).

The procedure to reduce experimental tests and introduce numerical correlation models as procedure to analyse the behaviour of components manufactured with dry fiber + infusion combined is new and still under study its relevance.

According to visual inspection (external) of the panels already manufactured for the extraction of Level 2 Test Coupons, the impression is that superficial quality is clearly inferior than obtained using current manufacturing process (specially in omega stiffener internal surface) but the interface between skin and stiffeners seems to be indistinguishable from any other ply to ply interface in stacking sequence (what is expected to improve the behaviour of the component at these locations where debonding between skin and stiffener is usually a critical failure).

Curved Stiffened Panel

SOFIA Logo and Branding

WP1 Numerical Analysis