SOFIA Project

Started: 2021

Completion: 2023

Participants: Leader: ALESTIS AEROSPACE SL; Applus+ Laboratories, GRUPO ELASTICIDAD Y RESISTENCIA DE MATERIALES DE LA UNIVERSIDAD DE SEVILLA (GERM).

Funding: This project has received funding from Clean Sky 2 Joint Undertaking (JU) under grant agreement no. 101007984. The JU receives support from the European Union's Horizon 2020 research and innovation programme and Clean Sky 2 members other than the Union.

The SOFIA R&D project is part of the Clean Sky research programme, focused on developing breakthrough technologies to improve the environmental performance of airplanes and air transport.

Objectives:

Nowadays, most aero structures made of composite materials are based on an epoxy matrix that is cured in an autoclave and/or at high temperatures. These curing methods are energy intensive and leave a high ecological footprint.

In order to reduce this ecological cost, the EcoTech consortium is developing new manufacturing and curing processes:

• Manufacturing: new automated processes for belting unidirectional dry fibre or non-crimped fabrics (NCF).
• Curing: optimised infusion processes.

The objective of the SOFIA R&D project is to verify that aero structures manufactured with these new processes meet the certification requirements of the aeronautical sector.

The results of the tests will demonstrate the viability of the new manufacturing techniques and the potential of this technology.

The project is led by ALESTIS. Applus+ Laboratories, which specializes in structural testing of large composite panels, will carry out the test programme.

Methodology:

The validation process aims to test the behaviour and properties of the component.

The validation process has been designed from the most elementary level up to the structural component and has been divided into the following levels:

• Level 1 testing: characterisation of materials by determination of mechanical properties and basic allowable values; presizing of the component: for determination of the main failure
• Level 2 testing: validation of structural details by determination of allowable values for typical failure modes.
• Level 3 testing: validation of the structural component under typical compressive loads.

To increase flexibility in the test configuration and reduce the cost of the project, a combination of different sensor systems and non-contact measurement systems will be used. The following technologies will be installed:

• Strain gauges and displacement sensors to assess local stress-strain and displacement of the structure.
• Real-Time Digital Image Correlation (Real-Time DIC) and a quantitative methodology to assess stress-strain using DIC for the determination of the global deformation field.
• Photogrammetry techniques to ensure geometrical tolerance of the test setup
• Digital Image Correlation Technique (Real-Time DIC technique) in order to allow a better correlation with the FEM model.