Innovative solutions for metallic ribs or fittings introduced in a composite box to optimally deal with thermo-mechanical effects

Project Information

INNOHYBOX

Grant agreement ID: 785433

DOI

10.3030/785433

Project closed

EC signature date 14 February 2018

Start date 1 March 2018

End date 30 April 2021

Funded under

• SOCIETAL CHALLENGES - Smart, Green And Integrated Transport

Total cost

€ 749 682,50

EU contribution

€ 749 682,50

Coordinated by

FUNDACIO EURECAT
Spain

Periodic Reporting for period 2 - INNOHYBOX (Innovative solutions for metallic ribs or fittings introduced in a composite box to optimally deal with thermo-mechanical effects)

Reporting period: 2019-05-01 to 2021-04-30

Summary of the context and overall objectives of the project

Today design of hybrid aircraft structures, such as wings of the business jet where skin and spar could be made in composite and internal ribs in aluminium, requires more robust models to understand the design drivers for components and assembly optimization to lead to weight optimization.

Clearly, the benefit for the society will that the design of hybrid structures optimized in weight will bring to less fuel consumption then generating less CO2 emissions.

The objective of this INNOHYBOX was to develop a wider understanding of the thermomechanical behaviour of a hybrid box with composite panels by including effects in joints with metallic ribs or fittings.

A building-up approach, from different materials CTE characterization up to the validation of a whole box assembly section, has been carried out to develop and validate the capacity to properly model the thermomechanical effect in hybrid assemblies.

Based on this developed Methodology, innovative design solution have been achieved for the metallic components of a hybrid composite wing-box.

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

At the begining the following main activities has been carried out:

* An accurate characterisation of thermal behaviour, starting with a thorough CTE evaluation of materials and composite through the full temperature range, considering laminate effect, moisture effect, etc.

* Started to develop the modellization in parallel of physical testing to demonstrate the capability to correctly evaluate the thermal behaviour of a composite box housing metallic components.

After a straight wing box section was produced and tested in different temperature conditions

A model and Methodology to design metallic ribs constrained in a full composite strcuture was after developed


The results are:

- Test results at coupon level done and reported
- Sub-element test are defined done and reported
- Wing box demostrator test done and reported
- Thermal models to correlate tests and predict behavior were done and correlated
- Method for design of metallic ribs constrained in a compote structure have been proposed

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)

The use of more accurate models to predict the thermomechanical behavoir of hybrid strcutures (metal/composite) will allow design optimization vs conservative models of today's design methodologies. The design optimization will lead to weight reduction the weight reduction will lead to CO2 emissions reducitons to benefit the overall society.

The achieved results at the end of the project are:

1. Provided an accurate characterisation of the hybrid composite box thermal behaviour, starting with a thorough CTE evaluation of materials and composite through the full temperature range, considering laminate effect, moisture effect, etc.
2. Studied the thermal influence at the component and assembly levels (closed box) to validate the modellization of thermal loads. The component level will allow to properly identify the sliding behaviour of an assembly of two components (considering typical assembly parameters such as fasteners, tolerances, liquid shim, sealant, paint, etc.).
3. Developed the modellization in parallel of physical testing to demonstrate the capability to correctly evaluate the thermal behaviour of a composite box housing metallic components.
4. A thermomechanical characterisation of complete box sections has been achieved d to validate the modellization capability. A larger closed box section shall provide a global validation of how the different components react and adjust with thermal loading.
5. Performed a design phase, following and based on the previous points, proposign new solutions for ribs and another type of metallic component, such as a spar, selected with the Topic Manager.

Wing Wob designed for testing experimentally the developed models