3D OBSERVATION OF DELAMINATION IN CARBON FIBREREINFORCED COMPOSITES UNDER REMOTE MODE II LOADING THROUGH IN SITU COMPUTED TOMOGRAPHY

Delamination is a prevalent and life-limiting failure mode in laminated composites, with mode II delamination, driven by in-plane shear, being particularly difficult to characterise. Conventional edge-monitoring techniques are inherently limited, as they cannot capture the three-dimensional (3D) evolution of the delamination front and the associated damage mechanisms. Building on our group's recent work demonstrating the first in situ X-ray computed tomography (CT) experiment for visualising mode II delamination, this paper presents preliminary results from an ongoing study focused on capturing successive delamination migration events in multidirectional laminates. The investigated specimens feature a +45°//−45° delamination interface and ±45° angled plies. A custom-designed in situ four-point bending rig is employed for the experiments. The proposed in situ CT technique enables mesoscale visualisation of delamination migration within the bulk of the specimen-a capability beyond the reach of conventional edge-monitoring techniques. These results underscore the potential of in situ CT to advance the understanding of mode II fracture evolution in composite laminates.