Unravelling In-Situ constituent Properties in fibre-reinforced composites: digital volume correlation applied to synchrotron computed tomography images (InSituPro)

Designing and generating accurate methodologies to assess mechanical properties of fibre-reinforced composites has been and still is an arduous challenge. The challenges are interrelated with the structural variability and complexity present in these structures and lead to inherent scatter in numerical models utilizing those property values. In this study, the aim is to develop an efficient and accurate methodology to counteract the present bottlenecks by implementing computed tomography of particle-filled glass fibre epoxy composites at voxel sizes below 500 nm. This will allow digital volume correlation (DVC) to generate 3D strain resolutions down to 8-15 μm. By blending these strain maps with novel reduction schemes, the objective is to accurately measure matrix and interface properties such as the interfacial normal and shear strength and toughness, the friction coefficient for interfacial sliding and the fatigue debond growth rates. The in situ measurement of these constituent properties will offer a quantum leap in understanding the micromechanical behaviour of fibre reinforced composites. The InSituPro methodology is therefore bound to provide essential input data for micromechanical models, present at the bottom of a multi-scale hierarchical pyramid, where structural design is born.