Charline van Innis
PhD student
Ir. at UCLouvain in 2020

Main project: New extrinsic toughening solutions for composite/metal joints: processing, characterization, testing and modelling
Funding: FRIA
Supervisor(s): Thomas Pardoen

In aerospace, several structural components combine composite and metallic parts that must be joined together. Adhesive bonding is an attractive solution that avoids stress concentrations such as caused by mechanical fasteners while the bonding step can be integrated in the manufacturing process. One remnant problem is the lower fracture resistance of the joint compared to the adherents. The objective of the thesis is to improve the joint integrity by investigating extrinsic toughening mechanisms. Three mechanisms are proposed. For the first one, the architecture of the joint will be modified by inserting holes or a pattern on the metal adherent to stop or deflect the crack. The second will be based on co-cured TP/TS interfaces allowing crack trapping in a tough zone. For the last one, an additional layer will be added near the joint in order to increase the energy dissipation during crack propagation. The effect of each one on joint toughness improvement will be investigated. Each can be used alone, but their combination will also be investigated. The proposed approach is based on experimentation and simulation. First, the materials must be selected before manufacturing the joints via the different techniques. Then, mechanical characterization will allow to assess the impact of the chosen mechanism on the joint toughness. In order to understand the failure mechanisms taking place, morphological and chemical characterization will be needed, but also nanoindentation to determine the local properties. Finally, multiscale modelling of the joint will allow, once the model will have been validated, to optimize the joint and to investigate the combination of the three mechanisms mentioned previously.

IMMC main research direction(s):
Processing and characterisation of materials

finite elements
fracture mechanics
hybrid and architectured materials

Research group(s): IMAP