Interlaminar Fracture of Fiber-Hybrid Composite Laminates: A Multiscale Approach

Project Information

INFORM

Grant agreement ID: 101108965

DOI

10.3030/101108965

Project closed

EC signature date 11 October 2023

Start date 1 December 2023

End date 30 November 2025

Funded under

• Marie Skłodowska-Curie Actions (MSCA)

Total cost

No data

EU contribution

€ 175 920,00

Coordinated by

KATHOLIEKE UNIVERSITEIT LEUVEN
Belgium

Periodic Reporting for period 1 - INFORM (Interlaminar Fracture of Fiber-Hybrid Composite Laminates: A Multiscale Approach)

Reporting period: 2023-12-01 to 2025-11-30

Summary of the context and overall objectives of the project

Carbon-fibre-reinforced polymer (CFRP) composites are essential for the next generation of high-performance lightweight structures, particularly in the aerospace and automotive sectors. However, these materials are prone to delamination, a failure mode where the composite layers separate. Predicting and preventing this is critical, as current engineering practices often lead to heavy 'over-designed' components to ensure safety.

The INFORM project was motivated by the need to understand how these internal cracks grow and migrate within multidirectional, thin-ply composites. The overall objective was to move from trial-and-error testing toward a reliable multiscale approach that combines advanced mathematical modelling with high-resolution 3D imaging. By establishing the technical foundations for more damage-tolerant designs, the project contributes directly to the EU’s 2030 climate objectives. Lighter composite structures enable significant fuel savings and a lower carbon footprint in transportation, addressing key environmental and economic needs within the EU’s 624 M€ composite market.

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

The INFORM project successfully integrated high-fidelity numerical simulations with pioneering experimental validation. A major achievement was the development of a custom, X-ray transparent mechanical testing rig. This allowed researchers, for the first time, to observe the 3D development of internal shear-driven cracks (mode II delamination) in situ using X-ray computed tomography (CT).

Key technical achievements include:
- Successful capture of delamination fronts and delamination migration events within the material bulk at a micro-scale resolution of 3.5 μm.
- Identification of complex 'zig-zag' fracture patterns in angle-ply laminates, providing volumetric evidence of how local microstructures dictate material failure.
- The project developed and validated a numerical design tool capable of predicting these failure paths with high accuracy, benchmarking them against real-time experimental data.

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)

INFORM moved beyond the current state of the art by challenging the 2D assumptions of existing international standards (such as ASTM D7905) and conventional edge-monitoring techniques. While traditional methods only monitor the edges of a specimen, our in situ CT approach proved that critical damage often occurs internally before it becomes visible on the surface.

The project proposed a new standardised protocol for 3D characterisation of shear-driven fracture. The potential impact is a shift toward 'virtual testing', where high-fidelity models reduce the need for expensive and time-consuming physical experiments. To ensure further uptake, future work will focus on integrating these 3D imaging datasets into industrial certification frameworks. This success has already secured follow-up funding for the FWO PATTERN project and supported the researcher’s transition to a faculty position at Politecnico di Milano.

In situ rig and capture of fibre bridging