In the context of the ecological transition and efforts to reduce the carbon footprint of materials, the incorporation of bio-based components into composites represents a major strategic opportunity.
Among these solutions, the use of plant-based fibers (such as flax or hemp) as a substitute for synthetic reinforcements in composites is attracting growing interest. Indeed, these plant fibers exhibit competitive tensile properties, with specific stiffness levels comparable to those of glass fibers.
However, these natural fibers also have defects (kink bands, etc.) as well as natural variability in structure and morphology that can affect their fracture properties and the performance of parts in service. A thorough understanding of the damage mechanisms in plant fibers is therefore necessary to enable their use in high-value-added applications. A few studies in the literature have examined damage at the plant fiber scale, using in situ mechanical testing under X-ray tomography.
However, a number of questions remain unanswered to this day: where does damage initiation occur within the fiber? What are the characteristic lengths involved during fracture? How does the composite matrix interact with the fiber? To answer these questions, a number of obstacles must be overcome regarding (i) the manage of fracture tests down to the single-fiber scale, (ii) the characterization of damage at these small scales, and (iii) the identification of relevant parameters and lengths to be incorporated into fiber-scale damage models.

Applicant profile
A student currently enrolled in an engineering school or a Master’s 2 program in mechanical engineering or materials science, with a strong interest in experimentation, image analysis, and/or numerical modeling. Candidates with a background in both experimental and numerical methods will be particularly sought after. A specialization in bio-based composites, material damage, or digital image correlation would be a plus. Knowledge of X-ray tomography is also desirable but not a strict requirement.