3D micro-rheology of concentrated fibre suspensions with non-newtonian suspending fluids

Owing to their very interesting specific physical and mechanical properties and their cost-efficient processing, fiber reinforced polymer composites (FRPC) are being increasingly used to make semi-structural, structural and multi-functional components in the aeronautic, electric and automotive industries.

These composite materials are made of complex networks of connected and entangled straight or wavy fibers impregnated by a polymer matrix. During the forming process, the liquid polymer matrix that flows through the complex anisotropic network of reinforcing fibers may induce severe deformation phenomena (e.g. compaction, elongation and shear) that can negatively affect the fibers, therefore altering the end use properties of the composites and reduce their potentialities.

In this project, micro-scale experimental and numerical data (micro-rheometry experiments and fast 3D imaging, modeling and simulation with HPC methods) will be collected and used to build new rheological models at meso-scale, through a rigorous up-scaling process.

The objective is to connect micro-scale phenomena to meso-scale behaviour and answer some of the crucial questions below:

• What are the spatial distributions and orientations of the fibers in the matrix?
• How do fibers or fiber bundles translate, rotate and deform in the suspension flow?
• How many fiber-fiber contacts per fiber are there and how do these contacts evolve?
• What are the impacts of such microstructural phenomena on the meso-scale stress levels?
• Is a continuum meso-scale description of the system relevant and if yes, what are its properties?
• What information can we use to improve the knowledge and the control at the process scale?